Peculiar Electrical and Magnetic Properties of La(Ba)MnO₃ Thin Films

Abstract

In this article it is reviewed on enigmatic electrical and magnetic properties of La(Ba)Mn0 3 thin films, useful for tunable microwave filters. As-grown films have well separated insulating to metallic (Tp) and paramagnetic to ferromagnetic (Tc) transition temperatures, which can be understood from the phase separation model. The film shows negative magnetoresistance (MR) caused by normal double exchange coupling effect, and positive MR which is interpreted by a magnetostriction effect. The phase separation is caused by crystal strain in the film. By annealing these two temperatures, Tp and Tc, become more separated, implying a size reduction of ferromagnetic grains. The phase separation scenario can be confirmed by ferromagnetic resonance (FMR) showing doublet signals. The FMR indicates anisotropic phase transition which supports the magnetostriction model. Moreover, the narrow FMR signals suggest high spin ordering and good crystallinity.

High Resolution X-Ray Diffraction Analyses of (La,Sr)MnO<sub>3</sub>/ZnO/Sapphire(0001) Double Heteroepitaxial Films

“…Deposition conditions for the LSMO overlayer were varied as a function of the substrate temperature (Ts: 650˚C -750˚C) and the oxygen partial pressure (Po). Details of the film fabrication can be referred in the previous papers [1,4].…”

“…Perovskite (La,Sr)MnO 3 (LSMO) manganate shows versatile electrical and magnetic properties such as colossal magnetoresistance [1] and is a p-type semiconductor at higher temperatures. While ZnO is an n-type widegap semiconductor which is studied as transparent conductive oxide for thin film transistors and display applications, since it is transparent for visible light but absorbs UV light.…”

ESR Study of (La,Ba)MnO3/ZnO Nanostructure for Resistive Switching Device

“…Due to a number of competitive interactions, the ground state of bulk and thin films of La 1- x Me x MnO 3 is often phase separated and usually characterized by a coexistence of highly conductive ferromagnetic (FM) phase and poorly conductive paramagnetic (PM) or charge-ordered phases [ 2 ]. Such complexity of the properties of perovskite manganites has become the point of attraction for a vast number of researchers around the world [ 2 , 5 , 6 ]. It is expected that this class of materials will create the foundation for various applications, such as low-field magnetoresistance sensors, resistive switching devices, and others [ 6 , 7 ].…”

“…Such complexity of the properties of perovskite manganites has become the point of attraction for a vast number of researchers around the world [ 2 , 5 , 6 ]. It is expected that this class of materials will create the foundation for various applications, such as low-field magnetoresistance sensors, resistive switching devices, and others [ 6 , 7 ].…”

Double-layer fabrication of cubic-manganites/hexagonal-ZnO on various substrates by ion beam sputtering, and variable electrical property

“…2) And they show phase transitions, at high temperatures they are paramagnetic insulator or p-type semiconductor while at low temperatures they are ferromagnetic metal. 2,3) The thin films of LBMO (LSMO) frequently show phase separation consisting of ferromagnetic metallic (FM) grain and charge ordered insulating (COI) phase with decreasing temperature. 3) These interests pushed various researchers to study LBMO and LSMO thin films all over the world.…”