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SUMMARY:ICMAB PhD Thesis: Rare-earth nitride thin films: growth study and c
 haracterization
DESCRIPTION:<p style="text-align: justify\;">PhD Candidate: <strong>Ana Mel
 éndez</strong>\, from the MPI-CPFS group at ICMAB-CSIC</p>\n<p style="tex
 t-align: justify\;"><strong>Abstract</strong>:</p>\n<p>Rare-earth mononitr
 ides (RENs) are a family of materials that combine semiconducting and magn
 etic properties\, making them promising candidates for spintronic and magn
 eto-electronic applications. However\, their propensity to form nitrogen v
 acancies\, which act as electron donors\, together with their extreme air 
 sensitivity\, has complicated their experimental investigation and led to 
 contradictory reports of their intrinsic properties. Although modern ultra
 -high-vacuum thin film growth techniques have significantly improved the q
 uality of available samples\, comprehensive studies relating growth condit
 ions to the structural\, electronic\, magnetic\, and optical properties of
  RENs remain limited.</p>\n<p>This thesis presents a systematic investigat
 ion of the growth and characterization of epitaxial HoN\, SmN\, and YbN th
 in films grown by molecular beam epitaxy under moderate growth conditions.
  Film quality and physical properties were studied using a combination of 
 in situ X-ray photoelectron spectroscopy (XPS)\, reflection high-energy el
 ectron diffraction (RHEED)\, and electrical transport measurements\, compl
 emented by ex situ X-ray diffraction (XRD) and spectroscopic ellipsometry 
 (SE). In-situ XPS was used to monitor the electronic&nbsp\;structure\, con
 firming the semiconducting character of all investigated materials. The in
 fluence of nitrogen vacancies on the electronic structure of SmN was inves
 tigated using X-ray absorption spectroscopy (XAS) and XPS. Magnetization m
 easurements on optimized and mildly nitrogen deficient HoN films revealed 
 a saturation moment substantially lower than the value predicted by Hund's
  rules\, attributed to intrinsic effects. Small concentrations of nitrogen
  vacancies produced only minor changes in the magnetic properties. The opt
 ical properties of SmN\, HoN\, and YbN were investigated by ex situ SE\, w
 hich allowed to determine band-gap energies\, resistivities\, and free car
 rier concentrations depending on nitrogen deficiency.</p>\n<p>Overall\, th
 is work demonstrates that the structural\, electronic\, magnetic\, and opt
 ical properties of rare earth mononitrides are highly sensitive to growth 
 conditions and stoichiometry. The methodologies developed provide a robust
  framework for the controlled synthesis and characterization of high quali
 ty REN thin films\, thereby contributing to a deeper understanding of the 
 relationship between defects\, electronic structure\, and the functional p
 roperties of this class of materials.</p>\n<p><strong style="font-size: 12
 .16px\;">Supervisors</strong></p>\n<ul>\n<li>&nbsp\;Isabel Alonso\, ICMAB-
 CSIC</li>\n<li>Simone Altendorf\, MPI-CPFS</li>\n<li>\n</li></ul>\n<p><str
 ong>PhD Committee</strong></p>\n<ul>\n<li>President: Jordi Fraxedas\, ICN2
 \, Spain</li>\n<li>Secretary: Mariona Coll\, ICMAB-CSIC\, Spain</li>\n<li>
 Vocal: Frank Güell\, UB\, Spain</li>\n</ul>\n<p>University: Universitat A
 utònoma de Barcelona (UAB)</p>\n<p>PhD Programme: Matereils Science</p>\n
 <p>IN-PERSON and Online (Register&nbsp\;<a href="https://zoom.us/webinar/r
 egister/WN_4dbSuKinRp29rqrlAYqwZQ#/registration" target="_blank" rel="noop
 ener noreferrer">HERE</a>)</p>\n<p><a href="https://icmab.es/ana-melendez-
 will-defend-her-phd-thesis-on-27-november-2026">MORE INFORMATION</a></p>
DTSTART:20261127T090000
DTEND:20261127T225959
LOCATION:Sala d'Actes MATGAS and ONLINE
CATEGORIES:Barcelona Nanocluster
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