4f和3d电子调控下的新型In和Te基稀土1：3型半导体化合物的磁输运和结构

In the study, novel magnetic intermetallics with a structural formula of R(X,T)3 (R=rare earth; X= indium, tellurium; T=3d transition metal) were designed and prepared using arc melting and powder metallurgy technologies. X-ray powder diffraction was used to check the phase in R(X,T)3 and a Rietveld structural refinement method was used to determine the crystal structure and atomic occupations. Based on these experimental data, the first principle theory was employed to investigate the structural stabilities of these intermetallics. These studies is to find out the correlations between phase formation & stabilities of R(X,T)3 and the contents of rare earths and 3d transition metals. The magnetic and transports properties of R(X,T)3 were measured using SQUID, PPMS etc. The theoretical model, which matches the experiment well, was constructed for investigating the various magnetic structures and its effects on the electronic scatters in electro-transport induced by the 4f-3d or 3d-3d interactions. For understanding the magnetic and transport characteristics of these novel R(X,T)3 intermetallics, the densities of status were calculated with the first principle theory. The moments and banding structures could be determined. It is helpful to understand the essential issues - the relationship between the magneto-transport characteristics and structures and magnetic properties. The study is expected to supply some valuable references for the novel magnetic electron materials.

本项课题设计了由4f（稀土）和3d（磁性元素）过渡簇金属共掺杂的新型半导体基R(T,X) 1：3型（R=稀土；T＝3d过渡簇金属；X＝In, Te）化合物。应用电弧熔炼和粉末冶金烧结方法制备这些化合物。应用变温XRD和Rietveld结构精修方法测定化合物的晶体结构，确定原子占位，在此基础上应用第一性原理研究R(T,X) 1：3型化合物的结构稳定性。揭示R(T,X) 1：3型化合物的形成及其稳定性与4f及3d金属及其掺杂量之间的关系。应用SQUID和PPMS等多种实验手段测定化合物的磁、电性能。建立与实验相符的磁输运理论模型，研究4f-3d和3d-3d作用诱发的各种复杂磁性结构，以及这些磁性结构对于输运中电子的各种散射作用。应用第一性原理研究化合物的磁性和输运特征。计算磁矩，并确定化合物的带宽。通过这些研究，揭示化合物中的电子输运与结构和磁性之间的本质。为探索新型磁电子材料提供实验依据。

通过四年的研究，共计制备出合成28个新型4f和3d金属共掺杂的R(In,T) 1：3、Cu(In,R/T)Te 1：1：2型稀土-In-3d过渡簇金属稀磁合金化合物。发现了室温铁磁性的新型Co基稀磁合金化合物，可以作为新型磁电子材料，具有潜在的应用前景。3d过渡簇金属含量与合金的晶体结构和磁性有很强的关联性，并同时诱发结构和磁性的转变。在Te基1：1：2半导体发现了外加磁场诱发的铁磁相和抗磁相的竞争磁现象，低场条件下铁磁性占主导地位，高场有利于抗磁性。系统地研究了4f和3d金属共掺杂对于1：3、1：1：2型合金化合物的晶体结构稳定性的影响，发现原子尺寸和元素的电负性差是主要因素，原子半径小的重稀土级化合物的结构更稳定。微结构研究表明：稀土有利于晶粒的细化和均匀性。磁输运研究表明：电输运和磁相具有很强的关联性，电相变与磁相变同时发生。机理性研究表明：合金化合物的电特性与电子结构密切相关，电子在不同轨道间的转化是主因。至今已在Journal of Alloys and Compounds, Journal of Applied Physics，Journal of Solid State Chemistry等SCI期刊发表学术论文14篇，EI论文7篇。另外, 发表核心期刊论文5篇。参加了学术会议5次，发表了会议论文5篇。发明专利授权1项，申请1项。