Study On Perovskite Manganese Oxide And Its Application In Sensor

Perovskite-type manganese oxide is a class of materials which present colossal magnetoresistance(CMR)effect and magnetothermal effect.In recent years,people have a new understanding of the mechanism of the CMR effect.And the modulation of Curie temperature,as well as the investigation of application about CMR,has been well achieved.However,the Curie temperature of most of manganese oxide possessed excellent physics properties is lower than room temperature.Therefore,How to obtain manganese oxide possessed excellent physics properties near room temperature is an important work.In this thesis,we had carried out some investigation about this aspect.And La2,3(Ca0.6Ba0.4)1/3MnO3(LCBMO)material with excellent properties was obtained experimentally.The results show that magnetoresistance of LCBMO thin film changes linearly with both temperature and external magnetic field near room temperature,indicating that the material can be acted as sense material of temperature and magnetic field.Based on these,we designed and fabricated a temperature&magnetic-field thin film sensor and its supporting data acquisition system.The main work includes:1.The LCBMO bulk was prepared by sol-gel method,and the LCBMO film structure was obtained by depositing the LCBMO bulk on SiO2 substrate by pulsed laser deposition.The structure and magnetic and electrical properties of bulk and thin films were measured by XRD,Profiler system and VSM.The results indicate that the optimal annealing temperature of the LCBMO thin film is 8000C,and Curie temperature of LCBMO material is near room temperature,in which magnetoresistance is linearly responsive to both temperature and magnetic field.2.Temperature&magnetic field sensor based on LCBMO thin film and its supporting data acquisition system were designed and fabricated.The detail is as follows.The voltage amplifying circuit is designed,and the voltage signal is collected by the data acquisition card.Besides,we also compiled a set of date acquisition software based on LabVIEW platform.The software contains parameter setting,data acquisition,digital filtering,parameter computation and obtaining,data storage and display,and other functions.3.Based on the as-designed temperature&magnetic field thin film sensor,voltage amplification circuit and data acquisition system,both the performance of LCBMO material and the program of sensor system reliability were verified.