The Study Of Magnetoresistance Effect In Doping Manganite Perovskite

As one of magnetism properties in the magnetism materials, magnetoresistance (MR) effect shows the magnitude about resistivity dependence of the magnetic field .The time when people focus on magnetoresistance effect is the last ten years.After MR effect was discovered from the multilayered films Fe/Co by Baibich et al in 1988, Helmolt et al got the same result from La_2／3Ba_1／3MnO_x films. From that on, more effort to study the MR effect were made. For the reason that the MR effect has us potential values in theoretical and practical research,One are still interested in the study of the MR effect.In this thesis, we give a systematic discussion on the discovery and the process of the study of magnetoresistance effect, how to get the materials which can make MR effect. From the experimental study point of view, we devise a scaling system for high (low)-temperature resistance and magnetoresistance, by using the system, the resistance and magnetoresistance properties of the materials is investigated. We propose a model to analysis the mechanism of MR effect by using a Monte Carlo technique We present the results of our Monte Carlo calculation in the last part of the thesis To some extent, theoretical calculation is found to be agreement with experimental results.