Magnetic properties of La_0.60Sr_0.40MnO₃ thin films on SrTiO₃ and buffered Si substrates with varying thickness

Authors

Aswini K. Pradhan, Center for Materials Research, Norfolk State UniversityFollow
D. Hunter, Norfolk State University, Norfolk, Virginia
T. Williams, Norfolk State University, Norfolk, Virginia
B. Lasley-Hunter, Norfolk State University, Norfolk, Virginia
R. Bah, Norfolk State University, Norfolk, Virginia
H. Mustafa, Norfolk State University, Norfolk, Virginia
Rakhim R. Rakhimov, Center for Materials Research, Norfolk State UniversityFollow
J. Zhang, University of Nebraska - Lincoln
David J. Sellmyer, University of Nebraska-LincolnFollow
E. E. Carpenter, Virginia Commonwealth University, Richmond, Virginia
D. R. Sahu, National Cheng Kung University, Tainan 701, Taiwan
J.-L. Huang, National Cheng Kung University, Tainan 701, Taiwan

Date of this Version

1-23-2008

Comments

Published by Am Inst of Physics. J. Appl. Phys. 103, 023914 2008. Copyright 2008. Permission to use. http://www.aip.org/.

Abstract

La_0.60Sr_0.40MnO₃ (LSMO) thin films of varying thickness from 12 to 55 nm were deposited using the pulsed-laser deposition technique onto single-crystalline SrTiO₃ (STO) and STO-buffered Si substrates. The T _c of LSMO films grown on STO-buffered Si substrates decreases faster than films directly grown on STO with decreasing film thickness. The LSMO/STO film with thickness of 55 nm shows T _c at about 360 K, which is close to the bulk value, whereas T _c LSMO film on STO-buffered Si film of similar thickness is reduced to 320 K. This difference is attributed to the strain and interfacial disorders in LSMO film on STO/Si. The film surface morphology is influenced by the film thickness. Oxygenation of LSMO films on STO-buffered Si affects the T _c minimally but improved the overall magnetization of the films due to better oxygenation, which is also the case for postannealing the sample at elevated temperatures. The thermomagnetic history effects observed in LSMO films of STO-buffered Si indicate the presence of inhomogeneity, mostly at the interface, which influences the magnetic properties significantly.