Structure And Electromagnetic Transport Properties Of R-In-M(R=Nd, Gd; M=Co, Mn)1:3Intermetallic Compounds

As being a novel magnetoelectric functional material, the magnetic semiconductor has potential application in electronic information field. Based on many literatures in related field, we has designed a novel magnetic semiconductor, where the raw materials are indium, rare earth element and the3d transition metals such as manganese and cobalt with a composition of1:3ratio between the rare earth and mixtures of indium and3d transition metals. The ordered structure with magnetic anisotropy is expected to form by the coupling interaction between3d electrons of transition metal and4f electrons of the rare earth. The electronic transport could be easily controlled by this magnetic structure.RIn3-xTx(R=Nd,Gd; T=Mn,Co) were prepared using vacuum Arc-melting under an atmosphere of Argon gas. The phases in these compounds were check by X-ray diffractometer with Cu radiation, the planar indices were determined with a TREOR program. The crystal structures, magnetic properties and electronic transport were investigated with Rietveld method and magnetic and electric measurements, respectively.X-ray diffraction analyses reveal that RIn3-xMnx (R=Nd, Gd) crystallize in AuCu3type structure with space group of Pm-3m and Z=1. In one unit cell, the1a (0,0,0) and3c(1/2,1/2,0) crystal positions are occupied by R and (In, Mn). Mn substitution for indium is confirmed. The lattice parameters are a=4.741(4)-4.641(6)A with V=106.69A3-100.00A3for RIn3-xMnx and a=4.605(5)-4.570(2)A, V=97.59A3-95.27A3for GdIn3-xMnx.In Co-rich region, the main phase of RC05is observed in RCo3-xInx (R=Nd,Gd; x=0,0.1,0.2,0.3), the lattice parameters and unit volumes increase with increasing the contents of indium.The magnetic analyses show complex magnetic phase relations at various Mn contents in RIn3-xMnx, which are paramagnetic for x=0and a mixture of paramagnetic and ferromagnetic for0<x<0.3.However, a low temperature magnetic phase is detected at2K, the magnetic moments increase with the applied field in the range from0to50kOe, it could not reach at the saturation status. The contribution to cocivity of Mn is confirmed in RIn3-xMnx by increasing Mn content.The electric transports of RIn3-xMnx (R=Nd, Gd) follow a semimetal rule with an equation of p=p0+aTn. With increasing Mn content, the intrinsic resistivity of p0and the magneto-electron scattering coefficienta tend to increase. It implies that the spins contribute to electronic transport. With the increase of temperature, the indices n tends to go up. It implies that the content of metallic phase increases with Mn content. However, the compound is still semimetal since the n<2.