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Title: Separation of the Strain and Finite Size Effect on the Ferromagnetic Properties of La0.5Sr0.5CoO3 Thin Films

Abstract

The ferromagnetic properties of epitaxial La0.5Sr0.5CoO3 thin films have been studied. The magnetic transition is affected by both strain and finite thickness. We have used a series of films of different thicknesses and on different substrates in order to quantitatively determine the change in Curie temperature contributed by each effect. The phase diagram of TC versus in-plane strain suggests that the ferromagnetic transition temperature is suppressed by tensile strain and enhanced by compressive strain. The general method of separating strain and finite thickness effects should be applicable to any ordering phase transition in thin films.

Authors:
; ; ;
Publication Date:
Research Org.:
Brookhaven National Laboratory (BNL) National Synchrotron Light Source
Sponsoring Org.:
Doe - Office Of Science
OSTI Identifier:
980448
Report Number(s):
BNL-93366-2010-JA
Journal ID: ISSN 0003-6951; APPLAB; TRN: US201015%%1833
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; COBALT OXIDES; CURIE POINT; FERROMAGNETISM; FILMS; LANTHANUM OXIDES; PHASE DIAGRAMS; SIZE; STRAINS; STRONTIUM OXIDES; SUBSTRATES; THICKNESS; THIN FILMS; TRANSITION TEMPERATURE; national synchrotron light source

Citation Formats

Xie, C., Budnick, J, Wells, B, and Woicik, J. Separation of the Strain and Finite Size Effect on the Ferromagnetic Properties of La0.5Sr0.5CoO3 Thin Films. United States: N. p., 2007. Web. doi:10.1063/1.2803220.
Xie, C., Budnick, J, Wells, B, & Woicik, J. Separation of the Strain and Finite Size Effect on the Ferromagnetic Properties of La0.5Sr0.5CoO3 Thin Films. United States. doi:10.1063/1.2803220.
Xie, C., Budnick, J, Wells, B, and Woicik, J. Mon . "Separation of the Strain and Finite Size Effect on the Ferromagnetic Properties of La0.5Sr0.5CoO3 Thin Films". United States. doi:10.1063/1.2803220.
@article{osti_980448,
title = {Separation of the Strain and Finite Size Effect on the Ferromagnetic Properties of La0.5Sr0.5CoO3 Thin Films},
author = {Xie, C. and Budnick, J and Wells, B and Woicik, J},
abstractNote = {The ferromagnetic properties of epitaxial La0.5Sr0.5CoO3 thin films have been studied. The magnetic transition is affected by both strain and finite thickness. We have used a series of films of different thicknesses and on different substrates in order to quantitatively determine the change in Curie temperature contributed by each effect. The phase diagram of TC versus in-plane strain suggests that the ferromagnetic transition temperature is suppressed by tensile strain and enhanced by compressive strain. The general method of separating strain and finite thickness effects should be applicable to any ordering phase transition in thin films.},
doi = {10.1063/1.2803220},
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}
}
  • We have used high-resolution extended x-ray absorption fine-structure and diffraction techniques to measure the local structure of strained La0.5Sr0.5CoO3 films under compression and tension. The lattice mismatch strain in these compounds affects both the bond lengths and the bond angles, though the larger effect on the bandwidth is due to the bond-length changes. The popular double exchange model for ferromagnetism in these compounds provides a correct qualitative description of the changes in Curie temperature TC, but quantitatively underestimates the changes. A microscopic model for ferromagnetism that provides a much stronger dependence on the structural distortions is needed.
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