狄拉克半金属候选材料NdSbTe中的巨负磁阻效应

Giant negative magneto resistance in the dirac semimetallic candidate NdSbTe

目的:探究狄拉克半金属候选材料NdSbTe单晶样品的新奇量子效应。方法:通过化学气相输运法制备NdSbTe单晶样品,利用X射线衍射对样品的结构进行了表征;利用物性测量系统和磁性测量系统分别测量了NdSbTe的电输运性质和磁性。结果:根据磁化率χ(T)随温度的变化关系可以断定NdSbTe单晶样品在T N≈3.4 K处存在磁相变,通过居里-外斯定律拟合进一步确定NdSbTe单晶在T N处的磁相变为顺磁态向反铁磁态转变。电输运性质测量表明,在不加磁场时,NdSbTe表现出半导体的行为,随着磁场的增加,电阻随温度升高而降低,呈现出巨负磁阻效应。结论:在T=3.4 K,NdSbTe发生了由顺磁态到反铁磁态的相变;在2~100 K范围内,NdSbTe具有巨负磁阻效应,当温度T=2 K、磁场μ0H=8 T时负磁阻最大可以达到-99.7%,该效应可能来源于反铁磁转变与近藤散射。

Aims:This paper aims to probe the novel quantum effects of the Dirac semimetallic candidate NdSbTe.Methods:NdSbTe single crystal samples were prepared by the chemical vapor transport method;and the structure of the sample was characterized using an X-ray diffractometer.The electrical transport properties of NdSbTe and its magnetism were measured.Results:According to magnetic susceptibilityχ(T),it could be concluded that NdSbTe single crystal had a magnetic transition at T N≈3.4 K.It could be further determined of the magnetic transition of NdSbTe single crystal at T N from the paramagnetic state to the antiferromagnetic state by fitting with the Curie Weiss law.The measurement of its electrical transport properties showed that NdSbTe behaved as a semiconductor when no magnetic field was applied.With the increase of the magnetic field,the resistance would decrease with the increase of temperature,showing a giant negative magnetoresistance effect.Conclusions:At T=3.4 K,NdSbTe undergoes a phase transition from paramagnetism to antiferromagnetism.In the range of 2~100 K,NdSbTe exhibits a giant negative magnetoresistance effect.When the temperature T=2 K and the magnetic fieldμ0H=8 T,the maximum negative magnetic resistance can reach-99.7%,which may be attributed to antiferromagnetic transition and Kondo scattering.