反钙钛矿结构Mn3XN(X=Cu,Ni)薄膜的制备及其磁相变和电输运特性研究

The antiperovskite structure Mn3XN materials, especially, Mn3CuN and Mn3NiN exhibit plenty of physical properties, such as magnetostriction, near zero temperature coefficient of resistivity, magnetoresistance effects, and so on. Their electronic and magnetic transport and thermal expansion properties are closely related and influence with each other. The physical properties of the correspoonding 2D Mn3XN thin film materials are also worthy of waited.On the basis of preliminary studies, the series of Mn3XN(X=Cu,Ni)thin films with single antiperovskite structure will be prepared by magnetron sputtering in this subject.Their magnetic phase transition and the variation of the electronic transport properties would be measured and investigated by selecting different preparation processes and anealing treatment method. On the other hand, the mutual doping of Cu and Ni can further leads to the variation and to achieve the adjustment of their magnetic phase transition and electronic transport properties. The study on the relationship among the preparation process, microscopic composition and properties of a single antiperovskite structure Mn3XN(X=Cu,Ni)thin films make its controllable preparation possible. At the same time, more systematically and deeply understanding of the special physical properties and the mechanism in this kind of materials will lay the experimental and theoretical basis for the development of the variety of features in the Mn3XN thin films with varieties of features in the future.

反钙钛矿结构的Mn3XN材料,特别是Mn3CuN和Mn3NiN两类材料具有丰富的物理特性，如磁致伸缩、近零电阻温度系数、磁阻效应等，其电、磁输运和热膨胀性质紧密相关，彼此影响。相应的二维Mn3XN薄膜材料的物理性能同样值得期待。本课题拟在前期研究的基础上，利用磁控溅射方法，通过选择不同的制备参数和后退火处理制备出具有单一反钙钛矿结构的Mn3XN(X=Cu,Ni)系列薄膜，探讨其磁相变、电输运特性的变化规律。另外，Cu、Ni两元素的互掺杂可以进一步诱导这种变化，实现对其磁相变和电输运性质的调控。这使研究具有单一反钙钛矿结构的Mn3XN(X=Cu,Ni)薄膜其制备工艺、微观成分与性能的关联关系，实现Mn3XN材料的可控制备成为可能。同时对该类材料的特殊物性和产生机理更加系统深入地认识，为将来开发具有多种功能特性的Mn3XN薄膜奠定了实验基础和理论依据。

本研究采用磁控溅射方法，通过选择不同的制备参数制备出具有单一反钙钛矿结构的Mn3XN (X=Cu, Ni) 系列薄膜，探讨其磁相变、电输运特性的变化规律。另外，Cu、Ni两元素的互掺杂可以进一步诱导这种变化，实现对其磁相变和电输运性质的调控。我们首次发现：（1）Mn3NiNx系列薄膜的择优取向效应可以通过调整溅射时氮分量Nf的大小来达到和控制。（2）Mn3NiNx系列薄膜在低温呈现自旋玻璃态的特征。（3）Mn3Ni(Cu)N 薄膜表面形貌的演变和Cu掺杂对晶粒聚合主导的晶粒成长过程的影响紧密相关。（4）在Mn3NiN和Mn3CuN薄膜中分别存在反铁磁和亚铁磁基态，而其他Cu掺杂Mn3Ni(Cu)N 薄膜中反铁磁和亚铁磁态同时存在。（5）Cu含量的增加减弱了Mn3Ni(Cu)N薄膜中反铁磁相互作用而加强了亚铁磁相互作用，从而导致了磁转变以及奈尔温度TN的降低。同时，Cu的掺入增大了晶胞参数从而晶胞体积发生膨胀，构成了Mn-Mn键的距离，从而减弱了亚铁磁相互作用和居里温度TC的降低。 上述结果使研究具有单一反钙钛矿结构的Mn3XN (X=Cu, Ni) 薄膜其制备工艺、微观成分与性能的关联关系，实现Mn3XN材料的可控制备成为可能。同时对该类材料的特殊物性和产生机理更加系统深入地认识，为将来开发具有多种功能特性的Mn3XN薄膜奠定了实验基础和理论依据。