2种居里温度测量方法的理论计算及比较  

Comparison of two measurement methods for Curie temperatureand related theoretical calculation

作　　者：何学敏[1] 陈端卿 于振飞 苏坤宇 毛巍威[1] HE Xuemin;CHEN Duanqing;YU Zhenfei;SU Kunyu;MAO Weiwei(College of Science,Nanjing University of Posts and Telecommunications,Nanjing 210023,China;College of Electronic and Optical Engineering,Nanjing University of Posts and Telecommunications,Nanjing 210023,China)

机构地区：[1]南京邮电大学理学院,江苏南京210023 [2]南京邮电大学电子与光学工程学院,江苏南京210023

出　　处：《物理实验》2024年第3期9-14,共6页Physics Experimentation

基　　金：南京邮电大学校级科研基金项目(No.NY220205)。

摘　　要：以平均尺寸为63 nm的球形Ni颗粒为例,从理论和实验上探究了铁磁物理参量——居里温度.基于内聚能模型和金属振动熵2种理论,推导了球形铁磁纳米颗粒的居里温度与颗粒尺寸的关系,并由此计算出居里温度的理论值分别为350.3℃和351.0℃.采用综合热分析仪和振动样品磁强计分别测试了Ni纳米颗粒的热重/差热曲线及热磁曲线,其差热曲线的相变峰给出居里温度的数值为353.0℃,通过热磁曲线的居里-外斯内推法可以得到居里温度为350.0℃.经对比,2个实验值之间,以及所有理论值与实验值之间的误差均未超过3.0℃,说明模型适用性强,由热重/差热法测量居里温度具有可行性.The Curie temperature T C,a ferromagnetic physical parameter,was investigated theoretically and experimentally by taking 63 nm(average diameter)spherical Ni particles as an example.Based on the cohesive energy model and the theory of metal vibration entropy,the relationship between Curie temperature and particle size of spherical ferromagnetic nanoparticles was deduced from the two theoretical methods,and then the theoretical T C values were calculated to be 350.3℃and 351.0℃,respectively.TG/DTA curve and thermomagnetic curve(namely the magnetization M varies with the temperature T)were measured by thermogravimetric/differential thermal analyzer(TG/DTA)and vibrating sample magnetometer(VSM),respectively.The phase transition peak of DTA curve gave T C value of 353.0℃,and the linear extrapolation of M-1-T curve gave T C value of 350.0℃.The error between the two experimental values,as well as between all theoretical values and experimental values,was less than 3.0℃.This indicated that the model had strong applicability for the current study,and thus the TG/DTA method for measuring T C was reliable.

关 键 词：居里温度 尺寸依赖性 磁相变 居里-外斯定律 内聚能 

分 类 号：O493.2[理学—物理]