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Title: Observation of Room Temperature Ferromagnetic Behaviour in Cluster-Free, Co Doped HfO2 Films

Abstract

Extensive structural and magnetic analyses of Hf{sub 1-x}Co{sub x}O{sub 2} thin films grown by molecular beam epitaxy are reported. Nearly cobalt cluster-free film with x=0.04-0.1 was obtained via 100 {sup o}C growth, and Co ions are inferred to be located at interstitial site. Ferromagnetic behavior was observed up to 300 K in both magnetization curves and temperature dependence of the moment. Via post-oxygen-annealing studies, a qualitative correlation between saturation magnetization and oxygen vacancy concentration is established, consistent with the impurity-band exchange model, and that the occurrence of ferromagnetic insulator behavior in the Co doped HfO{sub 2} is more probable than Co doped ZnO, TiO{sub 2}, and SnO{sub 2} systems for doping concentrations under cation percolation threshold.

Authors:
; ; ; ; ; ; ; ; ;
Publication Date:
Research Org.:
Brookhaven National Laboratory (BNL) National Synchrotron Light Source
Sponsoring Org.:
Doe - Office Of Science
OSTI Identifier:
930522
Report Number(s):
BNL-80521-2008-JA
Journal ID: ISSN 0003-6951; APPLAB; TRN: US200904%%765
DOE Contract Number:
DE-AC02-98CH10886
Resource Type:
Journal Article
Resource Relation:
Journal Name: Applied Physics Letters; Journal Volume: 91
Country of Publication:
United States
Language:
English
Subject:
36 MATERIALS SCIENCE; AMBIENT TEMPERATURE; CATIONS; COBALT; DOPED MATERIALS; FERROMAGNETISM; HAFNIUM COMPOUNDS; INTERSTITIALS; MAGNETIZATION; MOLECULAR BEAM EPITAXY; OXYGEN; PERIPHERAL MODELS; SATURATION; TEMPERATURE DEPENDENCE; THIN FILMS; national synchrotron light source

Citation Formats

Chang,Y., Soo, Y., Lee, W., Huang, M., Lee, Y., Weng, S., Sun, W., Ablett, J., Kao, C., and et al. Observation of Room Temperature Ferromagnetic Behaviour in Cluster-Free, Co Doped HfO2 Films. United States: N. p., 2007. Web. doi:10.1063/1.2773746.
Chang,Y., Soo, Y., Lee, W., Huang, M., Lee, Y., Weng, S., Sun, W., Ablett, J., Kao, C., & et al. Observation of Room Temperature Ferromagnetic Behaviour in Cluster-Free, Co Doped HfO2 Films. United States. doi:10.1063/1.2773746.
Chang,Y., Soo, Y., Lee, W., Huang, M., Lee, Y., Weng, S., Sun, W., Ablett, J., Kao, C., and et al. Mon . "Observation of Room Temperature Ferromagnetic Behaviour in Cluster-Free, Co Doped HfO2 Films". United States. doi:10.1063/1.2773746.
@article{osti_930522,
title = {Observation of Room Temperature Ferromagnetic Behaviour in Cluster-Free, Co Doped HfO2 Films},
author = {Chang,Y. and Soo, Y. and Lee, W. and Huang, M. and Lee, Y. and Weng, S. and Sun, W. and Ablett, J. and Kao, C. and et al.},
abstractNote = {Extensive structural and magnetic analyses of Hf{sub 1-x}Co{sub x}O{sub 2} thin films grown by molecular beam epitaxy are reported. Nearly cobalt cluster-free film with x=0.04-0.1 was obtained via 100 {sup o}C growth, and Co ions are inferred to be located at interstitial site. Ferromagnetic behavior was observed up to 300 K in both magnetization curves and temperature dependence of the moment. Via post-oxygen-annealing studies, a qualitative correlation between saturation magnetization and oxygen vacancy concentration is established, consistent with the impurity-band exchange model, and that the occurrence of ferromagnetic insulator behavior in the Co doped HfO{sub 2} is more probable than Co doped ZnO, TiO{sub 2}, and SnO{sub 2} systems for doping concentrations under cation percolation threshold.},
doi = {10.1063/1.2773746},
journal = {Applied Physics Letters},
number = ,
volume = 91,
place = {United States},
year = {Mon Jan 01 00:00:00 EST 2007},
month = {Mon Jan 01 00:00:00 EST 2007}
}
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