La0.5-xYxBa0.5CoO3 polycrystals were prepared by solid state reaction. The substituting effects of Y for La on the magnetic and transport properties of the materials were studied systematically. The results indicate that substitution of Y induces two effects. Firstly, the charge transfer from Y to 3d orbital of Co happens. This causes the molecular magnetic moment to decrease. Secondly, the antiferromagnetic exchange interaction of Co ions appears. When the content of Y is less than or equal to 30%, the non-colinear structure of spins in materials is observed. When the content of Y is greater than 30%, the materials transit from predominant ferromagnetic state to predominant antiferromagnetic one. The conductive mechanism for the materials with different content of Y belongs to the variable range hopping conduction of polarons. The resistivity of materials increases sharply with increasing Y content.

The doping effects of Sm in La0.67Ca0.33MnO3 oxide were studied. The results show that with increasing the doping amount of Sm the phase transition temperature of metal-insulator for the materials decreases monotonically, the corresponding peak resistance increases rapidly, the Curie temperature decreases monotonically, and the magneto-resistance ratio increases quickly. The effects of Sm doping can be explained in terms of lattice effects.

La0.5-xYxBa0.5CoO3 polycrystals were prepared by solid state reaction. The substituting effects of Y for La on the magnetic and transport properties of the materials were studied systematically. The results indicate that substitution of Y induces two effects. Firstly, the charge transfer from Y to 3d orbital of Co happens. This causes the molecular magnetic moment to decrease. Secondly, the antiferromagnetic exchange interaction of Co ions appears. When the content of Y is less than or equal to 30%, the non-colinear structure of spins in materials is observed. When the content of Y is greater than 30%, the materials transit from predominant ferromagnetic state to predominant antiferromagnetic one. The conductive mechanism for the materials with different content of Y belongs to the variable range hopping conduction of polarons. The resistivity of materials increases sharply with increasing Y content.

用固相反应法制备了La0.5-xYxBa0.5CoO3多晶材料,系统研究了Y的替代对材料磁性和输运特性的影响,结果发现,Y的掺入主要产生了两种效应,一是Y向Co的3d轨道产生了电荷转移,使分子磁矩下降,二是出现了Co离子的反铁磁交换作用,当Y含量少于或等于0.3时,材料中出现了自旋的非共线结构.当Y含量大于0.3时,材料从铁磁态为主转变为反铁磁态为主.对不同Y含量的材料,其导电机制都属于极化子的变程跳跃导电,随Y含量增加,材料电阻率迅速增大.

在La0.67Ca0.33MnO3中进行了掺Gd研究，结果发现，经1400℃烧结的样品，获得了最佳的磁电阻效应。随掺Gd量增加，材料的相变温度逐渐下降，对应的峰值电阻率大幅度增加，居里温度逐渐下降，磁电阻比明显提高。掺入11%的Gd后，可以使磁电阻比提高一个数量级。这些变化可以用晶格效应来解释。

The Sm substituting effects for La in La0.67Ca0.33MnO3 have been studied systematically. With increasing Sm doping amount, the metal-isolator phase transition temperature for the samples decreases monotonically, the corresponding peak resistivity increases dramatically and the Curie temperature decreases monotonically. The substitution of La-Ca-Mn-O with 0.13% Sm for La improved the magnetoresistance ratio by an order of magnitude. The effects of doping with Sm can be explained in terms of the lattice effects. An irreversible MR behaviour was observed in the Sm-doped compound. This effect was enhanced with increasing Sm doping amount.

The giant magneto-impedance (GMI) effect has been observed in nanocrystalline FeCuCrVSiB films prepared by rf sputtering followed by an annealing treatment. The magnetic properties and the longitudinal and transverse GMI have been studied in detail. Field dependence and frequency spectra of GMI effect have been studied in the frequency range from 100 kHz to 13 MHz. Maximum GMI ratios as large as 50% and 25% were obtained at 13 MHz in the longitudinal and transverse cases, respectively. The field sensitivity of the longitudinal GMI is about 0.11% m/A at 13 MHz. The dependence of effective permeability on the frequency and magnetic field has been investigated.

Sandwich films with the structure FM/Ag/FM have been prepared by radio-frequency sputtering and then annealed at an optimized temperature (here FM represents the FeCuCrVSiB amorphous soft magnetic layer). The giant-magneto-impedance (GMI) effects for the samples have been studied as a function of alternating-current frequency (50 kHz to 13 MHz) and external magnetic field. When the frequency increases above a critical frequency f* (about 150 kHz), the GMI ratio increases quickly with increasing frequency, and reaches a maximum value at a characteristic frequency fm of about 4 MHz. GMI ratios at fm as large as 109% and 135% were obtained for longitudinal and transverse applied magnetic fields, respectively. These results are much better than those obtained for single-layer films, and the frequencies used in producing the effect are very low.