• Ross, Caroline A.
• Pelliciari, Jonathan
• Kumar, Abinash
• Ning, Shuai
• Rosenberg, Richard
• Bauer, Jackson
• Chen, Yuchia
• Kaczmarek, Allison
• Cho, Eunsoo
• Freeland, John W.
• Comin, Riccardo
• Lebeau, James
• Occhialini, Connor A.
• Groot, F. M. F. De
• Wang, Jianping

Abstract

<jats:title>Abstract</jats:title><jats:p>Complex oxide films stabilized by epitaxial growth can exhibit large populations of point defects which have important effects on their properties. The site occupancy of pulsed laser‐deposited epitaxial terbium iron garnet (TbIG) films with excess terbium (Tb) is analyzed, in which the terbium:iron (Tb:Fe)ratio is 0.86 compared to the stoichiometric value of 0.6. The magnetic properties of the TbIG are sensitive to site occupancy, exhibiting a higher compensation temperature (by 90 K) and a lower Curie temperature (by 40 K) than the bulk Tb<jats:sub>3</jats:sub>Fe<jats:sub>5</jats:sub>O<jats:sub>12</jats:sub> garnet. Data derived from X‐ray core‐level spectroscopy, magnetometry, and molecular field coefficient modeling are consistent with occupancy of the dodecahedral sites by Tb<jats:sup>3+</jats:sup>, the octahedral sites by Fe<jats:sup>3+</jats:sup>, Tb<jats:sup>3+</jats:sup> and vacancies, and the tetrahedral sites by Fe<jats:sup>3+</jats:sup> and vacancies. Energy dispersive X‐ray spectroscopy in a scanning transmission electron microscope provides direct evidence of Tb<jats:sub>Fe</jats:sub> antisites. A small fraction of Fe<jats:sup>2+</jats:sup> is present, and oxygen vacancies are inferred to be present to maintain charge neutrality. Variation of the site occupancies provides a path to considerable manipulation of the magnetic properties of epitaxial iron garnet films and other complex oxides, which readily accommodate stoichiometries not found in their bulk counterparts.</jats:p>

Topics

• impedance spectroscopy
• Oxygen
• iron
• Curie temperature
• point defect
• Terbium