摘要
采用传统固相反应法制备多晶样品(La_(0.9)Eu_(0.1))_(4/3)Sr_(5/3)Mn_2O_7,测量了样品的磁化强度与温度关系曲线(M-T),并且采用数值方法研究了该多晶样品的磁性及磁卡效应。利用正交多项式最小二乘拟合方法对钙钛矿锰氧化物(La_(0.9)Eu_(0.1))_(4/3)Sr_(5/3)Mn_2O_7的磁化强度曲线M(H,T)进行拟合,再根据拟合的数据计算出样品的Arrott曲线和磁熵变值。研究发现:该样品处于低温时系统呈现铁磁性,而处于高温时系统呈现出顺磁性;当温度在Tc3D≈75 K附近,系统发生了一级相变而且出现较大的磁熵变值,样品在1 T外加磁场下的最大磁熵变值为1.53J·(kg·K)^(-1)。因此,该样品具有在液氢温区实现磁制冷的潜能。计算结果显示,拟合数据和实验数据误差较小,结果比较满意。说明此种方法适用于计算该样品的磁性和磁熵变。
The polycrystalline samples of double-layered manganite （La0.9Eu0.1）4/3Sr5/3Mn2O7 were prepared by the traditional solid state reaction. The magnetic and magnetocaloric properties of bilayered perovskite manganite （La0.9Eu0.1）4/3Sr5/3Mn2O7 were studied. The function M（ H,T） was obtained using orthogonal polynomial least square method fitting. The Arrott curves and magnetic entropy changes were calculated according to the magnetization curves. In the low temperature zone,the sample showed paramagnetic behavior. While in the high temperature zone,it exhibited ferromagnetic properties. Near the TC^3 D,while the sample exhibited the characteristic of a firstorder transition and gave a maximum magnetic entropy change of 1. 53 J·（ kg·K）^-1 under a 1 T magnetic field.This suggested that such materials might be applied to magnetic refrigeration in the temperature range of liquid hydrogen. The results fitted well with experimental data. This method could be used to calculate magnetic and the magnetic entropy changes of our samples.
出处
《中国稀土学报》
CAS
CSCD
北大核心
2016年第2期166-170,共5页
Journal of the Chinese Society of Rare Earths
基金
国家自然科学基金项目(11164019
51562032)
内蒙古自然科学基金项目(2015MS0109)
内蒙古高校科研重点项目基金(NJZZ11166
NJ10163
NJZY12202)
包头师范学院青年科学研究基金项目(BSYKJ2014-22)资助
关键词
磁性
磁熵变
相变
最小二乘法
magnetic property
magnetic entropy
phase transformation
least square method
