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Title: Magnetization anomalies and temperature-dependent hole localization in the Ca/sup 2 +/Fe/sup 4 +/Ga/sup 3 +/: yttrium iron garnet system

Abstract

The measurement of the temperature dependence of the magnetization, M/sub s/, between 4.2 and 300 K of epitaxial films of Y/sup 3+//sub 3-//sub x/Ca/sup 2+//sub x/Fe/sup 3+//sub 5-//sub y//sub -//sub x//sub '/ Ga/sup 3+//sub y/Fe/sup 4+//sub x//sub '/O/sup 2-//sub 12/, with x<0.4 and 0less than or equal toy<1.6, has shown low-temperature deviations from the molecular field theory of a two-sublattice Neel model, generally applicable to yttrium iron garnet with nonmagnetic substitutions. Molecular field calculations of M(x,y,T) have been performed, assuming a temperature-dependent concentration of Fe/sup 4 +/ ions due to the gradual localization of the uncompensated hole at the tetrahedral Fe/sup 3 +/ sites with the lowering of the temperature. The Fe/sup 4 +/ ions are assumed to form a third magnetic sublattice, which is ferromagnetically coupled to the octahedral Fe/sup 3 +/. The hole localization energy is observed to be on the order of 1--4 meV. The calculations are in good agreement with the experimental results.

Authors:
; ; ;
Publication Date:
Research Org.:
The Ohio State University, Columbus, Ohio 43210
OSTI Identifier:
5389904
Resource Type:
Journal Article
Resource Relation:
Journal Name: J. Appl. Phys.; (United States); Journal Volume: 63:8
Country of Publication:
United States
Language:
English
Subject:
36 MATERIALS SCIENCE; CALCIUM OXIDES; MAGNETIZATION; GALLIUM OXIDES; IRON OXIDES; YTTRIUM OXIDES; EXPERIMENTAL DATA; GARNETS; MEDIUM TEMPERATURE; TEMPERATURE DEPENDENCE; ULTRALOW TEMPERATURE; ALKALINE EARTH METAL COMPOUNDS; CALCIUM COMPOUNDS; CHALCOGENIDES; DATA; GALLIUM COMPOUNDS; INFORMATION; IRON COMPOUNDS; MINERALS; NUMERICAL DATA; OXIDES; OXYGEN COMPOUNDS; SILICATES; SILICON COMPOUNDS; TRANSITION ELEMENT COMPOUNDS; YTTRIUM COMPOUNDS; 360204* - Ceramics, Cermets, & Refractories- Physical Properties

Citation Formats

Pardavi-Horvath, M., Thavendrarajah, A., Wigen, P.E., and De Gasperis, P. Magnetization anomalies and temperature-dependent hole localization in the Ca/sup 2 +/Fe/sup 4 +/Ga/sup 3 +/: yttrium iron garnet system. United States: N. p., 1988. Web. doi:10.1063/1.340857.
Pardavi-Horvath, M., Thavendrarajah, A., Wigen, P.E., & De Gasperis, P. Magnetization anomalies and temperature-dependent hole localization in the Ca/sup 2 +/Fe/sup 4 +/Ga/sup 3 +/: yttrium iron garnet system. United States. doi:10.1063/1.340857.
Pardavi-Horvath, M., Thavendrarajah, A., Wigen, P.E., and De Gasperis, P. Fri . "Magnetization anomalies and temperature-dependent hole localization in the Ca/sup 2 +/Fe/sup 4 +/Ga/sup 3 +/: yttrium iron garnet system". United States. doi:10.1063/1.340857.
@article{osti_5389904,
title = {Magnetization anomalies and temperature-dependent hole localization in the Ca/sup 2 +/Fe/sup 4 +/Ga/sup 3 +/: yttrium iron garnet system},
author = {Pardavi-Horvath, M. and Thavendrarajah, A. and Wigen, P.E. and De Gasperis, P.},
abstractNote = {The measurement of the temperature dependence of the magnetization, M/sub s/, between 4.2 and 300 K of epitaxial films of Y/sup 3+//sub 3-//sub x/Ca/sup 2+//sub x/Fe/sup 3+//sub 5-//sub y//sub -//sub x//sub '/ Ga/sup 3+//sub y/Fe/sup 4+//sub x//sub '/O/sup 2-//sub 12/, with x<0.4 and 0less than or equal toy<1.6, has shown low-temperature deviations from the molecular field theory of a two-sublattice Neel model, generally applicable to yttrium iron garnet with nonmagnetic substitutions. Molecular field calculations of M(x,y,T) have been performed, assuming a temperature-dependent concentration of Fe/sup 4 +/ ions due to the gradual localization of the uncompensated hole at the tetrahedral Fe/sup 3 +/ sites with the lowering of the temperature. The Fe/sup 4 +/ ions are assumed to form a third magnetic sublattice, which is ferromagnetically coupled to the octahedral Fe/sup 3 +/. The hole localization energy is observed to be on the order of 1--4 meV. The calculations are in good agreement with the experimental results.},
doi = {10.1063/1.340857},
journal = {J. Appl. Phys.; (United States)},
number = ,
volume = 63:8,
place = {United States},
year = {Fri Apr 15 00:00:00 EDT 1988},
month = {Fri Apr 15 00:00:00 EDT 1988}
}