振动样品磁强计在磁黏滞行为研究中的应用  

Application of Vibrating Sample Magnetometer in the Study of Magnetic Viscosity

作　　者：白琴[1] 何建明[1] 徐晖[1] 赵清[1] 

机构地区：[1]上海大学微结构重点实验室,上海200444

出　　处：《实验室研究与探索》2015年第4期5-7,12,共4页Research and Exploration In Laboratory

基　　金：国家自然科学基金资助项目(51001066);上海市科委重点支撑计划项目(13520500500)

摘　　要：介绍了振动样品磁强计(VSM)在磁黏滞测试中不同的测试方法,包括磁黏滞系数法、扫描速度法和等待时间法。其中磁黏滞系数法是先将样品正向饱和,然后加一个反向磁场到负矫顽力附近,保持该磁场不变,测量磁极化强度J随时间t的变化。扫描速度法是在不同扫描速率下测量相应的磁滞回线,得到矫顽力Hc与扫描速率d(H)/dt的关系,从而求得热涨落场Hf;等待时间法,先将样品正向饱和,然后磁场缓慢减小至负矫顽力附近,保持这个磁场不变,测量磁极化强度J随时间t的变化。通过磁黏滞研究,可以更好地了解磁性材料的磁性机理,同时使振动样品磁强计在实验中发挥更大的作用。The application of vibrating sample magnetometer has been expanded from the conventional test of magnetic materials to the study of magnetic viscosity. In this paper, different kinds of magnetic viscosity measurement were introduced, including the coefficient of magnetic viscosity method, the sweep rate method, and the waiting time method. The procedure in the coefficient of magnetic viscosity test： Initially, a magnetic field H is applied in the forward direction to achieve saturation of the magnetization of the material. The field is reversed on moving to the second or third quadrant, and then heht constant at μ0Ha. Over a limited range of time, the time-depenndent magnetization .J（t） is measured. The J（t） is supposed to he straight-line relation in the coefficient of magnetic viscosity method, but there is no effective, curvature. Magnetic field sweep rate measurements show the intrinsic coercivity, H, to be proportional to the logarithm of the field sweep rate, through measuring the hysteresis loops under different sweep rates. The fluctuation field, H1, is determined from the sweep rate method. The waiting time method is also called ＂one-step method＂. A magnetic fiehl H is applied firstly to achieve the saturation of the magnetization of the material, and the field is reduced slowly to the value around the negative coercivity, and then held constantly at μ0Ha. The time-dependent magnetization J（t） is measured for a relatively long period of time. The cite（t examples show that the magnetic mechanism of materials can be better understood hy the study in the magnetic viscosity and VSM plays a more important role based on the magnetic viscosity measurement.

关 键 词：振动样品磁强计 磁黏滞系数法 扫描速度法 等待时间法 

分 类 号：TG115.27[金属学及工艺—物理冶金]