磁场下电沉积制备CuCo颗粒膜的巨磁电阻效应

Giant magnetoresistance of CuCo granular films electrodeposited in magnetic field

在磁场下电沉积制备CuCo功能膜材料,研究膜层的巨磁电阻效应及磁性能。应用X射线衍射仪(XRD)对镀层微观结构随热处理温度的变化进行分析,采用四引线法及振动样品磁强计(VSM)测量膜层的磁性能。磁阻测试发现:磁感应强度为0.6T下制备的CuCo颗粒膜经500℃真空退火处理1h后,其巨磁电阻值较无磁场下制备的提高约25%,这是由于0.6T下制备的颗粒膜晶粒较致密,同时磁场减少了膜层内部缺陷,如杂质、夹杂等。样品磁滞回线表明:500℃真空退火处理1h后膜层具有最佳的磁性能,此时膜层中的单磁畴磁性粒子有助于提高巨磁电阻值。CuCo颗粒膜电沉积制备过程中施加磁场可以改善膜层的微观结构,使其具有更高的巨磁电阻效应。

CuCo granular films were prepared by electrodeposition in the stable magnetic field. The giant magnetoresistance and magnetic property of the films were studied. The composition and structure of the plating films were studied by XRD. The giant magnetoresistance of the films was measured by the four line method. Vibration sample magnetometer was used to measure the magnetic properties. The giant magnetoresistance r6sults show that the magnetoresistance of CuCo granular films prepared at 0.6 T after annealing at 500℃ for I h increases by 25% than that prepared without magnetic field after vacuum annealing. The reasons are that the crystal grains of films prepared at 0.6 T are more compact, and the defects in the film such as impurity and inclusion are reduced by the magnetic field. The hysteresis loops indicate that the granular film presents the optimal magnetism after annealing at 500℃ for 1 h. The single magnetic domain of particle in the film is contributed to promote the giant magnetoresistance. When the CuCo granular films are electrodeposited in the stable magnetic field, the microstructure of CuCo granular films is improved and the better giant magnetoresistance effect is obtained.