Staff directory Gustau Catalán Bernabé

Gustau Catalán Bernabé

ICREA Research Professor and Group Leader
Oxide Nanophysics



  • A Solar Transistor and Photoferroelectric Memory

    Pérez-Tomás A., Lima A., Billon Q., Shirley I., Catalan G., Lira-Cantú M. Advanced Functional Materials; 28 (17, 1707099) 2018. 10.1002/adfm.201707099. IF: 13.325

    This study presents a new self-powered electronic transistor concept “the solar transistor.” The transistor effect is enabled by the functional integration of a ferroelectric-oxide thin film and an organic bulk heterojunction. The organic heterojunction efficiently harvests photon energy and splits photogenerated excitons into free electron and holes, and the ferroelectric film acts as a switchable electron transport layer with tuneable conduction band offsets that depend on its polarization state. This results in the device photoconductivity modulation. All this (i.e., carrier extraction and poling) is achieved with only two sandwiched electrodes and therefore, with the role of the gating electrode being taken by light. The two-terminal solar-powered phototransistor (or solaristor) thus has the added advantages of a compact photodiode architecture in addition to the nonvolatile functionality of a ferroelectric memory that is written by voltage and nondestructively read by light. © 2018 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim

  • Flexoelectricity in antiferroelectrics

    Vales-Castro P., Roleder K., Zhao L., Li J.-F., Kajewski D., Catalan G. Applied Physics Letters; 113 (13, 132903) 2018. 10.1063/1.5044724. IF: 3.495

    Flexoelectricity (coupling between polarization and strain gradients) is a property of all dielectric materials that has been theoretically known for decades, but only relatively recently it has begun to attract experimental attention. As a consequence, there are still entire families of materials whose flexoelectric performance is unknown. Such is the case of antiferroelectrics: materials with an antiparallel but switchable arrangement of dipoles. These materials are expected to be flexoelectrically relevant because it has been hypothesised that flexoelectricity could be linked to the origin of their antiferroelectricity. In this work, we have measured the flexoelectricity of two different antiferroelectrics (PbZrO3 and AgNbO3) as a function of temperature, up to and beyond their Curie temperature. Although their flexocoupling shows a sharp peak at the antiferroelectric phase transition, neither flexoelectricity nor the flexocoupling coefficients are anomalously high, suggesting that it is unlikely that flexoelectricity causes antiferroelectricity. © 2018 Author(s).

  • Flexoelectricity in Bones

    Vasquez-Sancho F., Abdollahi A., Damjanovic D., Catalan G. Advanced Materials; 30 (9, 1705316) 2018. 10.1002/adma.201705316. IF: 21.950

    Bones generate electricity under pressure, and this electromechanical behavior is thought to be essential for bone's self-repair and remodeling properties. The origin of this response is attributed to the piezoelectricity of collagen, which is the main structural protein of bones. In theory, however, any material can also generate voltages in response to strain gradients, thanks to the property known as flexoelectricity. In this work, the flexoelectricity of bone and pure bone mineral (hydroxyapatite) are measured and found to be of the same order of magnitude; the quantitative similarity suggests that hydroxyapatite flexoelectricity is the main source of bending-induced polarization in cortical bone. In addition, the measured flexoelectric coefficients are used to calculate the (flexo)electric fields generated by cracks in bone mineral. The results indicate that crack-generated flexoelectricity is theoretically large enough to induce osteocyte apoptosis and thus initiate the crack-healing process, suggesting a central role of flexoelectricity in bone repair and remodeling. © 2018 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim

  • Piezoelectric Mimicry of Flexoelectricity

    Abdollahi A., Vásquez-Sancho F., Catalan G. Physical Review Letters; 121 (20, 205502) 2018. 10.1103/PhysRevLett.121.205502. IF: 8.839

    The origin of "giant" flexoelectricity, orders of magnitude larger than theoretically predicted, yet frequently observed, is under intense scrutiny. There is mounting evidence correlating giant flexoelectriclike effects with parasitic piezoelectricity, but it is not clear how piezoelectricity (polarization generated by strain) manages to imitate flexoelectricity (polarization generated by strain gradient) in typical beam-bending experiments, since in a bent beam the net strain is zero. In addition piezoelectricity changes sign under space inversion but giant flexoelectricity is insensitive to space inversion, seemingly contradicting a piezoelectric origin. Here we show that, if a piezoelectric material has its piezoelectric coefficient asymmetrically distributed across the sample, it will generate a nonzero bending-induced polarization impossible to distinguish from true flexoelectricity even by inverting the sample. The effective flexoelectric coefficient caused by piezoelectricity is functionally identical to, and often larger than, intrinsic flexoelectricity: our calculations show that, for standard perovskite ferroelectrics, even a tiny gradient of piezoelectricity (1% variation of piezoelectric coefficient across 1 mm) is sufficient to yield a giant effective flexoelectric coefficient of 1 μC/m, three orders of magnitude larger than the intrinsic expectation value. © 2018 American Physical Society.


  • Domain wall magnetoresistance in BiFeO3 thin films measured by scanning probe microscopy

    Domingo N., Farokhipoor S., Santiso J., Noheda B., Catalan G. Journal of Physics Condensed Matter; 29 (33, 334003) 2017. 10.1088/1361-648X/aa7a24. IF: 2.678

    We measure the magnetotransport properties of individual 71° domain walls in multiferroic BiFeO3 by means of conductive-atomic force microscopy (C-AFM) in the presence of magnetic fields up to one Tesla. The results suggest anisotropic magnetoresistance at room temperature, with the sign of the magnetoresistance depending on the relative orientation between the magnetic field and the domain wall plane. A consequence of this finding is that macroscopically averaged magnetoresistance measurements for domain wall bunches are likely to underestimate the magnetoresistance of each individual domain wall. © 2017 IOP Publishing Ltd.

  • Ferroelectrics as Smart Mechanical Materials

    Cordero-Edwards K., Domingo N., Abdollahi A., Sort J., Catalan G. Advanced Materials; 29 (37, 1702210) 2017. 10.1002/adma.201702210. IF: 19.791

    The mechanical properties of materials are insensitive to space inversion, even when they are crystallographically asymmetric. In practice, this means that turning a piezoelectric crystal upside down or switching the polarization of a ferroelectric should not change its mechanical response. Strain gradients, however, introduce an additional source of asymmetry that has mechanical consequences. Using nanoindentation and contact-resonance force microscopy, this study demonstrates that the mechanical response to indentation of a uniaxial ferroelectric (LiNbO3) does change when its polarity is switched, and use this mechanical asymmetry both to quantify its flexoelectricity and to mechanically read the sign of its ferroelectric domains. © 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim

  • On the persistence of polar domains in ultrathin ferroelectric capacitors

    Zubko P., Lu H., Bark C.-W., Martí X., Santiso J., Eom C.-B., Catalan G., Gruverman A. Journal of Physics Condensed Matter; 29 (28, 284001) 2017. 10.1088/1361-648X/aa73c3. IF: 2.678

    The instability of ferroelectric ordering in ultra-thin films is one of the most important fundamental issues pertaining realization of a number of electronic devices with enhanced functionality, such as ferroelectric and multiferroic tunnel junctions or ferroelectric field effect transistors. In this paper, we investigate the polarization state of archetypal ultrathin (several nanometres) ferroelectric heterostructures: epitaxial single-crystalline BaTiO3 films sandwiched between the most habitual perovskite electrodes, SrRuO3, on top of the most used perovskite substrate, SrTiO3. We use a combination of piezoresponse force microscopy, dielectric measurements and structural characterization to provide conclusive evidence for the ferroelectric nature of the relaxed polarization state in ultrathin BaTiO3 capacitors. We show that even the high screening efficiency of SrRuO3 electrodes is still insufficient to stabilize polarization in SrRuO3/BaTiO3/SrRuO3 heterostructures at room temperature. We identify the key role of domain wall motion in determining the macroscopic electrical properties of ultrathin capacitors and discuss their dielectric response in the light of the recent interest in negative capacitance behaviour. © 2017 IOP Publishing Ltd.


  • A flexoelectric microelectromechanical system on silicon

    Bhaskar U.K., Banerjee N., Abdollahi A., Wang Z., Schlom D.G., Rijnders G., Catalan G. Nature Nanotechnology; 11 (3): 263 - 266. 2016. 10.1038/nnano.2015.260. IF: 35.267

    Flexoelectricity allows a dielectric material to polarize in response to a mechanical bending moment and, conversely, to bend in response to an electric field. Compared with piezoelectricity, flexoelectricity is a weak effect of little practical significance in bulk materials. However, the roles can be reversed at the nanoscale. Here, we demonstrate that flexoelectricity is a viable route to lead-free microelectromechanical and nanoelectromechanical systems. Specifically, we have fabricated a silicon-compatible thin-film cantilever actuator with a single flexoelectrically active layer of strontium titanate with a figure of merit (curvature divided by electric field) of 3.33MV â '1, comparable to that of state-of-the-art piezoelectric bimorph cantilevers. © 2016 Macmillan Publishers Limited.

  • Above-Bandgap Photovoltages in Antiferroelectrics

    Pérez-Tomás A., Lira-Cantú M., Catalan G. Advanced Materials; 28 (43): 9644 - 9647. 2016. 10.1002/adma.201603176. IF: 18.960

    The closed circuit photocurrent and open circuit photovoltage of antiferroelectric thin films were characterized both in their ground (antipolar) state and in their polarized state. A sharp transition happens from near zero to large photovoltages as the polarization is switched on, consistent with the activation of the bulk photovoltaic effect. The AFE layers have been grown by a solution processing method (sol?gel synthesis followed by spin coating deposition) onto fluorine-doped tin oxide (FTO), a transparent conducting oxide with low sheet resistance and a higher resilience to high-temperature processing than indium tin oxide and a standard for solar cells such as organometal trihalide perovskites. Light absorption confirmed that the PZO films are, as expected, wide-band gap semiconductors with a gap of 3.7.8 eV and thus highly absorbing in the near-ultraviolet range. On a virgin sample, there is no shortcircuit photocurrent, consistent with the antipolar nature of the ground state. As an external bias voltage is applied, the current remains negligible until suddenly, at the coercive voltage, a spike is observed, corresponding to the transient displacement current caused by the onset of polarization.

  • Enhanced flexoelectric-like response in oxide semiconductors

    Narvaez J., Vasquez-Sancho F., Catalan G. Nature; 538 (7624): 219 - 221. 2016. 10.1038/nature19761. IF: 38.138

    Flexoelectricity is a property of all dielectric materials whereby they polarize in response to deformation gradients such as those produced by bending. Although it is generally thought of as a property of dielectric insulators, insulation is not a formal requirement: in principle, semiconductors can also redistribute their free charge in response to strain gradients. Here we show that bending a semiconductor not only generates a flexoelectric-like response, but that this response can in fact be much larger than in insulators. By doping single crystals of wide-bandgap oxides to increase their conductivity, their effective flexoelectric coefficient was increased by orders of magnitude. This large response can be explained by a barrier-layer mechanism that remains important even at the macroscale, where conventional (insulator) flexoelectricity otherwise tends to be small. Our results open up the possibility of using semiconductors as active ingredients in electromechanical transducer applications. © 2016 Macmillan Publishers Limited, part of Springer Nature. All rights reserved.

  • Ferroelectric Domain Structures in Low-Strain BaTiO3

    Everhardt A.S., Matzen S., Domingo N., Catalan G., Noheda B. Advanced Electronic Materials; 2 (1, 1500214) 2016. 10.1002/aelm.201500214. IF: 0.000

    Epitaxial strain in ferroelectric films offers the possibility to enhance the piezoelectric performance utilizing low crystal symmetries and high density of domain walls. Ferroelectric BaTiO3 has been predicted to order in a variety of phases and domain configurations when grown under low strain on low mismatched substrates, but little experimental evidence of that region of the phase diagram exist. Here, epitaxial BaTiO3 thin films are grown on NdScO3 substrates under ≈0.1% strain. A monoclinic ca1/ca2 phase, with 90° periodic in-plane domain configuration and small additional out-of-plane component of polarization, is stabilized at room temperature and investigated using piezoelectric force microscopy and X-ray diffraction. Above 50 °C, this phase is transformed into an a/c phase with alternating in-plane and out-of-plane polarizations and forming zigzag domain walls between up-polarized and down-polarized superdomains. Both types of domain patterns are highly anisotropic, giving rise to very long domain walls. Above 130 °C, the paraelectric phase is observed. The occurrence of a phase transition close to room temperature, a low symmetry ca1/ca2 phase, and the formation of periodic domains make of this material a promising candidate for high piezoelectric response. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim

  • Flexoelectric MEMS: Towards an electromechanical strain diode

    Bhaskar U.K., Banerjee N., Abdollahi A., Solanas E., Rijnders G., Catalan G. Nanoscale; 8 (3): 1293 - 1298. 2016. 10.1039/c5nr06514c. IF: 7.760

    Piezoelectricity and flexoelectricity are two independent but not incompatible forms of electromechanical response exhibited by nanoscale ferroelectrics. Here, we show that flexoelectricity can either enhance or suppress the piezoelectric response of the cantilever depending on the ferroelectric polarity and lead to a diode-like asymmetric (two-state) electromechanical response. © 2016 The Royal Society of Chemistry.


  • Dielectric relaxation in YMnO3 single crystals

    Adem U., Mufti N., Nugroho A.A., Catalan G., Noheda B., Palstra T.T.M. Journal of Alloys and Compounds; 638: 228 - 232. 2015. 10.1016/j.jallcom.2015.02.207. IF: 2.999

    We have investigated the origin of the dielectric relaxation in YMnO3 single crystals. Two distinct dielectric relaxation features were observed at low (200≤T≤373K) and high (300≤T≤450K) temperatures. Analysis of our detailed frequency, electrode and thickness dependent dielectric measurements and ac conductivity data as well as the use of single crystals allow us to get a comprehensive picture of these relaxations. The low temperature relaxation is attributed to the Maxwell-Wagner type effects originating from the dipoles at the surface while the high temperature one is suggested to originate from hopping of charge carriers resulting from the second ionization of oxygen vacancies. © 2015 Elsevier B.V. All rights reserved.

  • Ferroelectrics: Negative capacitance detected

    Catalan G., Jimenez D., Gruverman A. Nature Materials; 14 (2): 137 - 139. 2015. 10.1038/nmat4195. IF: 36.503

    [No abstract available]

  • Fracture toughening and toughness asymmetry induced by flexoelectricity

    Abdollahi A., Peco C., Millán D., Arroyo M., Catalan G., Arias I. Physical Review B - Condensed Matter and Materials Physics; 92 (9, 094101) 2015. 10.1103/PhysRevB.92.094101. IF: 3.736

    Cracks generate the largest strain gradients that any material can withstand. Flexoelectricity (coupling between strain gradient and polarization) must therefore play an important role in fracture physics. Here we use a self-consistent continuum model to evidence two consequences of flexoelectricity in fracture: the resistance to fracture increases as structural size decreases, and it becomes asymmetric with respect to the sign of polarization. The latter phenomenon manifests itself in a range of intermediate sizes where piezo- and flexoelectricity compete. In BaTiO3 at room temperature, this range spans from 0.1 to 50 nm, a typical thickness range for epitaxial ferroelectric thin films. © 2015 American Physical Society.

  • Giant reversible nanoscale piezoresistance at room temperature in Sr2IrO4 thin films

    Domingo N., López-Mir L., Paradinas M., Holy V., Železný J., Yi D., Suresha S.J., Liu J., Rayan Serrao C., Ramesh R., Ocal C., Martí X., Catalan G. Nanoscale; 7 (8): 3453 - 3459. 2015. 10.1039/c4nr06954d. IF: 7.394

    Layered iridates have been the subject of intense scrutiny on account of their unusually strong spin-orbit coupling, which opens up a narrow bandgap in a material that would otherwise be a metal. This insulating state is very sensitive to external perturbations. Here, we show that vertical compression at the nanoscale, delivered using the tip of a standard scanning probe microscope, is capable of inducing a five orders of magnitude change in the room temperature resistivity of Sr2IrO4. The extreme sensitivity of the electronic structure to anisotropic deformations opens up a new angle of interest on this material, with the giant and fully reversible perpendicular piezoresistance rendering iridates as promising materials for room temperature piezotronic devices. This journal is © The Royal Society of Chemistry.

  • Large Flexoelectric Anisotropy in Paraelectric Barium Titanate

    Narvaez J., Saremi S., Hong J., Stengel M., Catalan G. Physical Review Letters; 115 (3, 037601) 2015. 10.1103/PhysRevLett.115.037601. IF: 7.512

    The bending-induced polarization of barium titanate single crystals has been measured with an aim to elucidate the origin of the large difference between theoretically predicted and experimentally measured flexoelectricity in this material. The results indicate that part of the difference is due to polar regions (short-range order) that exist above TC and up to T∗≈200-225°C. Above T∗, however, the flexovoltage coefficient still shows an unexpectedly large anisotropy for a cubic material, with (001)-oriented crystals displaying 10 times more flexoelectricity than (111)-oriented crystals. Theoretical analysis shows that this anisotropy cannot be a bulk property, and we therefore interpret it as indirect evidence for the theoretically predicted but experimentally elusive contribution of surface piezoelectricity to macroscopic bending-induced polarization. © 2015 American Physical Society. © 2015 American Physical Society.

  • Mechanical tuning of LaAlO3/SrTiO3 interface conductivity

    Sharma P., Ryu S., Burton J.D., Paudel T.R., Bark C.W., Huang Z., Ariando, Tsymbal E.Y., Catalan G., Eom C.B., Gruverman A. Nano Letters; 15 (5): 3547 - 3551. 2015. 10.1021/acs.nanolett.5b01021. IF: 13.592

    In recent years, complex-oxide heterostructures and their interfaces have become the focus of significant research activity, primarily driven by the discovery of emerging states and functionalities that open up opportunities for the development of new oxide-based nanoelectronic devices. The highly conductive state at the interface between insulators LaAlO3 and SrTiO3 is a prime example of such emergent functionality, with potential application in high electron density transistors. In this report, we demonstrate a new paradigm for voltage-free tuning of LaAlO3/SrTiO3 (LAO/STO) interface conductivity, which involves the mechanical gating of interface conductance through stress exerted by the tip of a scanning probe microscope. The mechanical control of channel conductivity and the long retention time of the induced resistance states enable transistor functionality with zero gate voltage. © 2015 American Chemical Society.

  • Nanomechanics of flexoelectric switching

    Očenášek J., Lu H., Bark C.W., Eom C.B., Alcalá J., Catalan G., Gruverman A. Physical Review B - Condensed Matter and Materials Physics; 92 (3, 035417) 2015. 10.1103/PhysRevB.92.035417. IF: 3.736

    We examine the phenomenon of flexoelectric switching of polarization in ultrathin films of barium titanate induced by a tip of an atomic force microscope (AFM). The spatial distribution of the tip-induced flexoelectricity is computationally modeled both for perpendicular mechanical load (point measurements) and for sliding load (scanning measurements), and compared with experiments. We find that (i) perpendicular load does not lead to stable ferroelectric switching in contrast to the load applied in the sliding contact load regime, due to nontrivial differences between the strain distributions in both regimes: ferroelectric switching for the perpendicular load mode is impaired by a strain gradient inversion layer immediately underneath the AFM tip; while for the sliding load regime, domain inversion is unimpaired within a greater material volume subjected to larger values of the mechanically induced electric field that includes the region behind the sliding tip; (ii) beyond a relatively small value of an applied force, increasing mechanical pressure does not increase the flexoelectric field inside the film, but results instead in a growing volume of the region subjected to such field that aids domain nucleation processes; and (iii) the flexoelectric coefficients of the films are of the order of few nC/m, which is much smaller than for bulk BaTiO3 ceramics, indicating that there is a "flexoelectric size effect" that mirrors the ferroelectric one. ©2015 American Physical Society.

  • Nanoscale conductive pattern of the homoepitaxial AlGaN/GaN transistor

    Pérez-Tomás A., Catalàn G., Fontserè A., Iglesias V., Chen H., Gammon P.M., Jennings M.R., Thomas M., Fisher C.A., Sharma Y.K., Placidi M., Chmielowska M., Chenot S., Porti M., Nafría M., Cordier Y. Nanotechnology; 26 (11, 115203) 2015. 10.1088/0957-4484/26/11/115203. IF: 3.821

    The gallium nitride (GaN)-based buffer/barrier mode of growth and morphology, the transistor electrical response (25-310 C) and the nanoscale pattern of a homoepitaxial AlGaN/GaN high electron mobility transistor (HEMT) have been investigated at the micro and nanoscale. The low channel sheet resistance and the enhanced heat dissipation allow a highly conductive HEMT transistor (Ids>1 A mm-1) to be defined (0.5 A mm-1 at 300 C). The vertical breakdown voltage has been determined to be ∼850 V with the vertical drain-bulk (or gate-bulk) current following the hopping mechanism, with an activation energy of 350 meV. The conductive atomic force microscopy nanoscale current pattern does not unequivocally follow the molecular beam epitaxy AlGaN/GaN morphology but it suggests that the FS-GaN substrate presents a series of preferential conductive spots (conductive patches). Both the estimated patches density and the apparent random distribution appear to correlate with the edge-pit dislocations observed via cathodoluminescence. The sub-surface edge-pit dislocations originating in the FS-GaN substrate result in barrier height inhomogeneity within the HEMT Schottky gate producing a subthreshold current. © 2015 IOP Publishing Ltd.

  • Persistence of ferroelectricity above the Curie temperature at the surface of Pb(Z n1/3 N b2/3) O3-12%PbTi O3

    Domingo N., Bagués N., Santiso J., Catalan G. Physical Review B - Condensed Matter and Materials Physics; 91 (9, 094111) 2015. 10.1103/PhysRevB.91.094111. IF: 3.736

    Relaxor-based ferroelectrics have been known for decades to possess a relatively thick surface layer ("skin") that is distinct from its interior. Yet while there is consensus about its existence, there are controversies about its symmetry, phase stability, and origin. In an attempt to clarify these issues, we have examined the surface layer of PZN-12%PT. While the bulk transitions from a ferroelastically twinned tetragonal ferroelectric state with in-plane polarization to a cubic paraphase at Tc=200C, the skin layer shows a robust labyrinthine nanodomain structure with out-of-plane polarization that persists hundreds of degrees above the bulk Curie temperature. Cross-sectional transmission electron microscopy analysis shows that the resilience of the skin's polarization is correlated with a compositional imbalance: lead vacancies at the surface are charge-compensated by niobium enrichment; the excess of Nb5+ - a small ion with d0 orbital occupancy - stabilizes the ferroelectricity of the skin layer. © 2015 American Physical Society.


  • Origin of the enhanced flexoelectricity of relaxor ferroelectrics

    Narvaez, J.; Catalan, G. Applied Physics Letters; 104 (16) 2014. 10.1063/1.4871686. IF: 3.515


  • Flexoelectric effect in solids

    Zubko, P.; Catalan, G.; Tagantsev, A.K. Annual Review of Materials Research; 43: 387 - 421. 2013. 10.1146/annurev-matsci-071312-121634. IF: 16.179

  • Local properties of the surface layer(s) of BiFeO3 single crystals

    Domingo, N.; Narvaez, J.; Alexe, M.; Catalan, G. Journal of Applied Physics; 113 2013. 10.1063/1.4801974. IF: 2.210

  • Thickness scaling of ferroelastic domains in PbTiO3 films on DyScO3

    Nesterov, O.; Matzen, S.; Magen, C.; Vlooswijk, A.H.G.; Catalan, G.; Noheda, B. Applied Physics Letters; 103 2013. 10.1063/1.4823536. IF: 3.794


  • Domain wall nanoelectronics

    Catalan, G.; Seidel, J.; Ramesh, R.; Scott, J.F. Reviews of Modern Physics; 84: 119 - 156. 2012. 10.1103/RevModPhys.84.119.

  • Elastic and anelastic relaxations in the relaxor ferroelectric Pb(Mg 1/3Nb 2/3)O 3: I. Strain analysis and a static order parameter

    Carpenter, M.A.; Bryson, J.F.J.; Catalan, G.; Howard, C.J. Journal of Physics Condensed Matter; 24 2012. 10.1088/0953-8984/24/4/045901.

  • Elastic and anelastic relaxations in the relaxor ferroelectric Pb(Mg 1/3Nb 2/3)O 3: II. Strainorder parameter coupling and dynamic softening mechanisms

    Carpenter, M.A.; Bryson, J.F.J.; Catalan, G.; Zhang, S.J.; Donnelly, N.J. Journal of Physics Condensed Matter; 24 2012. 10.1088/0953-8984/24/4/045902.

  • Magnetotransport at domain walls in BiFeO 3

    He, Q.; Yeh, C.-H.; Yang, J.-C.; Singh-Bhalla, G.; Liang, C.-W.; Chiu, P.-W.; Catalan, G.; Martin, L.W.; Chu, Y.-H.; Scott, J.F.; Ramesh, R. Physical Review Letters; 108 2012. 10.1103/PhysRevLett.108.067203.

  • Mechanical Writing of Ferroelectric Polarization

    Lu, H. ; Bark, C.W.; Esque de los Ojos, D.; Alcala, J. ; Eom, C. B.; Catalan, G. ; Gruverman, A. SCIENCE; 336 (6077): 59 - 61. 2012. DOI: 10.1126/science.1218693.

  • Structural, spectroscopic, magnetic and electrical characterization of Ca-doped polycrystalline bismuth ferrite, Bi 1xCa xFeO 3x/2 (x0.1)

    Sardar, K.; Hong, J.; Catalan, G.; Biswas, P.K.; Lees, M.R.; Walton, R.I.; Scott, J.F.; Redfern, S.A.T. Journal of Physics Condensed Matter; 24 2012. 10.1088/0953-8984/24/4/045905.

  • Surface phase transitions in BiFeO 3 below room temperature

    Jarrier, R.; Marti, X.; Herrero-Albillos, J.; Ferrer, P.; Haumont, R.; Gemeiner, P.; Geneste, G.; Berthet, P.; Schülli, T.; Cevc, P.; Blinc, R.; Wong, S.S.; Park, T.-J.; Alexe, M.; Carpenter, M.A.; Scott, J.F.; Catalan, G.; Dkhil, B. Physical Review B - Condensed Matter and Materials Physics; 85 2012. 10.1103/PhysRevB.85.184104.


  • Flexoelectric rotation of polarization in ferroelectric thin films.

    Catalan, G. ; Lubk, A.; Vlooswijk, A. H. G.; Snoeck, E.; Magen, C. ; Janssens, A.; Rispens, G.; Rijnders, G.; Blank, D. H. A.; Noheda, B. Nature Materials; 10: 963. 2011. .

  • Skin layer of BiFeO3 single crystals

    Martí, X.; Ferrer, P.; Herrero-Albillos, J.; Narvaez, J.; Holy, V.; Barrett, N.; Alexe, M.; Catalan, G. Physical Review Letters; 106 2011. 10.1103/PhysRevLett.106.236101.


  • Comment on "Nanometer resolution piezoresponse force microscopy to study deep submicron ferroelectric and ferroelastic domains" [Appl. Phys. Lett. 94, 162903 (2009)]----NO ES ARTICULO

    Vlooswijk, A.H.G.; Catalan, G.; Noheda, B. Applied Physics Letters; 97 2010. 10.1063/1.3467005.

  • Electric-field control of the metal-insulator transition in ultrathin NdNiO3 films

    Scherwitzl, R.; Zubko, P.; Lezama, I.G.; Ono, S.; Morpurgo, A.F.; Catalan, G.; Triscone, J.-M. Advanced Materials; 22: 5517 - 5520. 2010. 10.1002/adma.201003241.

  • Landau theory of domain wall magnetoelectricity

    Daraktchiev, M.; Catalan, G.; Scott, J.F. Physical Review B - Condensed Matter and Materials Physics; 81 2010. 10.1103/PhysRevB.81.224118.

  • Neutron diffraction study of the BiFeO3 spin cycloid at low temperature

    Herrero-Albillos, J.; Catalan, G.; Rodriguez-Velamazan, J.A.; Viret, M.; Colson, D.; Scott, J.F. Journal of Physics Condensed Matter; 22: 256001 - 256005. 2010. 10.1088/0953-8984/22/25/256001.

  • The β-to-γ transition in BiFeO 3: A powder neutron diffraction study

    Arnold, D.C.; Knight, K.S.; Catalan, G.; Redfern, S.A.T.; Scott, J.F.; Lightfoot, P.; Morrison, F.D. Advanced Functional Materials; 20: 2116 - 2123. 2010. 10.1002/adfm.201000118.

  • The flexoelectricity of barium and strontium titanates from first principles

    Hong, J.; Catalan, G.; Scott, J.F.; Artacho, E. Journal of Physics Condensed Matter; 22 2010. 10.1088/0953-8984/22/11/112201.


  • Domains in Ferroelectric Nanodots

    A. Schilling; D. Byrne; G. Catalan; K. G. Webber; Y. A. Genenko; G. S. Wu; J. F. Scott; J. M. Gregg Nano Letters; 9: 3359. 2009. .

  • Effect of chemical substitution on the Néel temperature of multiferroic Bi1¿xCaxFeO3

    G. Catalan; K. Sardar; N. S. Church; J. F. Scott; R. J. Harrison; S. A. T. Redfern Physical Review B; 79: 212415. 2009. 10.1103/PhysRevB.79.212415.

  • Effect of wall thickness on the ferroelastic domain size of BaTiO3

    G. Catalan; I. Lukyanchuk; A. Schilling; J. M. Gregg; J. F. Scott Journal of Materials Science; 44: 5307. 2009. 10.1007/s10853-009-3554-0.

  • Elastic and electrical anomalies at low-temperature phase transitions in BiFeO3

    S. A. T. Redfern; Can Wang; J. W. Hong; G. Catalan; J. F. Scott Journal of Physics Condensed Matter; 20: 452205. 2009. 10.1088/0953-8984/20/45/452205.

  • Epitaxial TbMnO3 thin films on SrTiO3 substrates: a structural study

    C. J. M. Daumont; D. Mannix; S. Venkatesan; G. Catalan; D. Rubi; B. J. Kooi; J. Th. M. De Hosson; B. Noheda Journal of Physics Condensed Matter; 21: 182001. 2009. 10.1088/0953-8984/21/18/182001.

  • Origin of ferroelastic domains in free-standing single-crystal ferroelectric films

    I. A. Luk¿yanchuk; A. Schilling; J.M. Gregg; G. Catalan; J.F. Scott Physical Review B; 79: 144111. 2009. 10.1103/PhysRevB.79.144111.

  • Physics and applications of BiFeO3

    G. Catalan; J. F. Scott Advanced Materials; 21: 2463 - 2485. 2009. 10.1002/adma.200802849.


  • Conduction at domain walls in oxide multiferroics

    J. Seidel; L. W. Martin; Q. He; Q. Zhan; Y.-H. Chu; A. Rother; M. E. Hawkridge; P. Maksymovych; P. Yu; M. Gajek; N. Balke; S. V. Kalinin; S. Gemming; H. Lichte; F. Wang; G. Catalan; J. F. Scott; N. A. Spaldin; J. Orenstein; R. Ramesh Nature Materials; 8: 229 - 234. 2008. 10.1038/nmat2373.

  • Conformal oxide coating of carbon nanotubes

    S. Kawasaki; G. Catalan; H. J. Fan; M. M. Saad; J. M. Gregg; M. A. Correa-Duarte; J. Rybczynski; F. D. Morrison; T. Tatsuta; O. Tsuji; and J. F. Scott Applied Physics Letters; 92 (5): 53109. 2008. 10.1063/1.2841710.

  • Fractal walls and domain size scaling in thin films of multiferroic BiFeO3

    G. Catalan; H. Béa; S. Fusil; M. Bibes; P. Paruch; A. Barthélémy; and J. F. Scott Physical Review Letters; 100: 27602. 2008. 10.1103/PhysRevLett.100.027602.

  • Landau Theory of Multiferroic Domain Walls

    M. Daraktchiev; G. Catalan; J. F. Scott Ferroelectrics; 375: 122 - 131. 2008. 10.1080/00150190802437969.

  • Progress in perovskite nickelate research

    G. Catalan Phase Transitions; 81: 729. 2008. 10.1080/01411590801992463.

  • ß phase and ¿-ß metal-insulator transition in multiferroic BiFeO3

    R. Palai; R. S. Katiyar; H. Schmid; P. Tissot; S. J. Clark; J. Robertson; S. A. Redfern; G. Catalan; J. F. Scott Physical Review B - Condensed Matter and Materials Physics; 77: 14110. 2008. 10.1103/PhysRevB.77.014110.

  • Solution-process coating of vertical ZnO nanowires with ferroelectrics

    S. Kawasaki; H. J. Fan; G. Catalan; F. D. Morrison; T. Tatsuta; O. Tsuji; J. F Scott Nanotechnology; 19: 375302. 2008. 10.1088/0957-4484/19/37/375302.