La0.7Sr0.3MnO3单晶外延薄膜制备及其磁电阻特性

为制得性能良好的涂层导体用La0.7Sr0.3MnO3(LSMO)缓冲层薄膜、研究LSMO薄膜的低磁场磁电阻效应,利用高分子辅助化学溶液沉积法,在LaAlO3(LAO)单晶基底上制备了一系列钙钛矿LSMO单晶外延薄膜.考虑氩气和氧气退火气氛对LSMO成相的影响,研究了氩气退火条件下样品的织构、形貌情况和氧气退火条件下制得的样品的输运性质及磁电阻效应.研究结果表明:氩气下采用高分子辅助的化学溶液沉积法有利于制备出低成本、高性能的涂层导体用单一LSMO缓冲层;氧气下退火制得的薄膜c轴取向生长良好,并且电阻-温度曲线出现绝缘体-金属相变,其磁电阻值在200~300 K范围内不随温度变化,在1 T磁场室温下磁电阻值约为-26.0 %. 

Preparation of La0.7Sr0.3MnO3 Single-Crystal Epitaxial Films and Their Magnetoresistance Properties

In oder to obtain high quality single La0.7Sr0.3MnO3 (LSMO) buffer layers and study their low-field magnetoresistance (MR), a series of epitaxial films of perovskite manganites La0.7Sr0.3MnO3 (LSMO) deposited on the LaAlO3 (LAO) single crystal substrates were fabricated by the polymer-assisted chemical solution deposition method. Taking into account the influences of argon and oxygen annealing atmosphere on the LSMO phase formation, investigations were conducted on the surface morphology and texture of the specimens annealed in argon and the transport properties and colossal magnetoresistance (CMR) effect of the specimens annealed in oxygen. The results show that thick and high quality single LSMO buffer layers can be produced at low costs by the polymer-assisted chemical solution deposition method and annealing in argon atmosphere. The films fabricated in oxygen are found with good c-axis textured, and the MR measurements of the films shows a peak, corresponding to the insulator-metal (I-M) transition. The MR value does not change with the temperature between 200 to 300 K, and is about-26.0 % at room temperature in 1 T magnetic field.