MnBi1-xCrx（x=0.04,0.08,0.12,0.16）合金的晶体结构与磁性能

Crystal Structure and Magnetic Properties of MnBi1-xCrx（x=0.04,0.08,0.12,0.16） Alloys

本研究采用真空电弧熔炼法制备了MnBi1-xCrx(x=0.04,0.08,0.12,0.16)系列合金,利用X射线衍射仪(XRD)、Rietveld全谱拟合和振动样品磁强计(VSM)研究和测定MnBi1-xCrx系列合金样品的晶体结构和磁性能。结果发现,退火后的样品主相是低温相(LTP)MnBi(空间群:P63/mmc(194))。Rietveld全谱拟合分析确定每个样品中各相的含量并解析出主相MnBi1-xCrx的晶体结构。M(M=Bi,Cr)原子之间的原子间距dM-M随着掺杂量增大而增大。M原子与Mn原子的间距dM-Mn随着掺杂量增大而减小。在400 K时趋于饱和,且在掺杂量小于x=0.12时,饱和磁化强度随着掺杂量的增加而增大,在掺杂量大于x=0.12时,饱和磁化强度已经达到饱和,为20.55 emμ/g,且不随掺杂含量的变化而变化。随着Cr含量的增加,矫顽力亦逐渐增加,并且在掺杂量为x=0.12时达到最大值。随着测试温度的上升,合金矫顽力均呈上升趋势。MnBi1-xCrx(x=0.04,0.08,0.12,0.16)的德拜温度分别为378.46 K,369.52 K,354.62 K和351.64 K。

MnBi1-xCrx(x=0.04,0.08,0.12,0.16)series alloys were prepared by vacuum arc melting method.The crystal structure and magnetic properties of the series alloy samples were investigated and determined by X-ray diffraction(XRD),Rietveld full-spectrum fitting and vibrating sample magnetometer(VSM).The results show that main phase of the annealed sample is a low temperature phase(LTP)MnBi(space group:P63/mmc(194)).Rietveld method is used to determine the content of each phase in each sample and to analyze the crystal structure of the main phase MnBi1-xCrx.The atomic distance dM-M between M(M=Bi,Cr)atoms increases with the increase of doping amount.The M atom and Mn atom distance dM-Mn decreases with the increase of doping amount.At 400K,it tends to be saturated,and when the doping amount is less than x=0.12,the saturation magnetization increases with the increase of doping amount.When the doping amount is greater than x=0.12,the saturation magnetization has reached saturation,which is 20.55emμ/g,and does not vary with the change in doping content.As the test temperature increases,the coercivity of the alloy increases.The Debye temperatures of MnBi1-xCrx(x=0.04,0.08,0.12,0.16)are 378.46K,369.52K,354.62Kand 351.64K,respectively.