resumo
Oxide multiferroic thin films and heterostructures offer a wide range of properties originated from intrinsic coupling between lattice strain and nanoscale magnetic/electronic ordering. La0.9Ba0.1MnO3 (LBM) thin-films and LBM/BaTiO3/LBM (LBMBT) heterostructures were grown on single crystalline [100] silicon and [0001] Al2O3 using RF magnetron sputtering to study the effect of crystallinity and induced lattice mismatch in the film on magnetic properties of deposited films and heterostructures. The thicknesses of the films on Al2O3 and Si are 70 and 145 nm, respectively, and for heterostructures are 40/30/40 nm on both substrates. The microstructure of the films, state of strain and growth orientations was studied by XRD and microscopy techniques. Interplay of microstructure, strain and magnetic properties is further investigated. It is known that the crystal structure of substrates and imposed tensile strain affect the physical properties; i.e. magnetic behavior of the film. The thin layer grown on Al2O3 substrate shows out-of-plane compressive strain, while Si substrate induces tensile strain on the deposited film. The magnetic transition temperatures (T-c) of the LBM film on the Si and Al2O3 substrates are found to be 195 K and 203 K, respectively, slightly higher than the bulk form, 185 K. The LBMBT heterostructure on Si substrate shows drastic decrease in magnetization due to produced defects created by diffusion of Ti ions into magnetic layer. Meanwhile, the Tc in LBMBT, increases in respect to other studied single layers and heterostructure, because of higher tensile strain induced at the interfaces. (C) 2017 Elsevier B.V. All rights reserved.
palavras-chave
EPITAXIAL MANGANITE FILMS; ROOM-TEMPERATURE; MAGNETORESISTANCE; FERROELECTRICITY; MULTIFERROICS; LA1-XBAXMNO3
categoria
Chemistry; Materials Science; Physics
autores
Vaghefi, PM; Baghizadeh, A; Willinger, M; Lourenco, AACS; Amaral, VS
nossos autores
Ali Baghi Zadeh
Bolseiro de pós-Doutoramento
Armando António Cardoso Dos Santos Lourenço
Professor Auxiliar
Pegah Mirzadeh Vaghefi
Bolseiro de pós-Doutoramento
Vitor Brás Sequeira Amaral
Professor CatedráticoProjectos
CICECO - Aveiro Institute of Materials (UID/CTM/50011/2013)
Multiferroics and magnetoelectrics for spintronics: barriers and interfaces (PTDC/CTM/099415/2008)
MULTIFOX: Nanometric Probing and Modification of Multiferroic Oxides (PTDC/FIS/105416/2008)
agradecimentos
This work was developed in the scope of the project CICECO-Aveiro Institute of Materials (Ref. FCT UID/CTM/50011/2013), financed by national funds through the FCT/MEC and when applicable co-financed by FEDER under the PT2020 Partnership Agreement. We would like to thank the financial support from the FCT project PTDC/FIS/105416/2008 "MULTIFOX" and PTDC/CTM/099415/2008 grants and FCT project SFRH/BD/51140/2010 in order to access all microscopes in pole of electron microscopy in Aveiro University.