ErGa3-xMnx disordered alloy is successfully prepared by the vacuum arc melting technology,and the crystal structure and magnetic properties are investigated by using the x-ray diffraction and magnetic measurements.The Rietveld structural analysis indicates that the ErGa3-xMnx crystallizes into a cubic structure with space group of Pm3m in Mn doping range of x=0-0.1.However,the disordered alloy with structural formula of Er0.8Ga2^Ⅰ(Ga^Ⅱ,Mn)0.4 as the second phase is separated from cubic phase for the samples with x=0.2 and 0.3,which is induced by substituting the(Ga^Ⅱ,Mn)-(Ga^Ⅱ,Mn)pair at 2e crystal position for the rare earth Er at 1 a site.The lattice parameters tend to increase with Mn content increasing due to the size effect at Ga(1.30A)site by substituting Mn(1.40A)for Ga.The paramagnetic characteristic is observed by doping Mn into ErGa3 at room temperature.With Mn content increasing from x=0 to 0.1,the magnetic susceptibilityχtends to increase.This phenomenon can be due to the increase of effective potential induced by doping Mn into ErGa3.However,the magnetic susceptibilityχcontinues to decrease with the increase of Mn content in a range of x>0.2,which is due to the phase separation from the cubic Er(Ga,Mn)3 to the hexagonal Er0.8Ga2(Ga,Mn)0.4.
The magnetisms of RCo_5(R = rare earth) intermetallics are systematically studied with the empirical electron theory of solids and molecules(EET).The theoretical moments and Curie temperatures agree well with experimental ones.The calculated results show strong correlations between the valence electronic structure and the magnetic properties in RCo_5 intermetallic compounds.The moments of RCo_5 intermetallics originate mainly from the 3d electrons of Co atoms and 4f electrons of rare earth,and the s electrons also affect the magnetic moments by the hybridization of d and s electrons.It is found that moment of Co atom at 2c site is higher than that at 3g site due to the fact that the bonding effect between R and Co is associated with an electron transformation from 3d electrons into covalence electrons.In the heavy rare-earth-based RCo_5 intermetallics,the contribution to magnetic moment originates from the 3d and 4f electrons.The covalence electrons and lattice electrons also affect the Curie temperature,which is proportional to the average moment along the various bonds.
Ce-doped Cu In Te2(CICT) semiconducting compounds are successfully synthesized. The phase structures, optical,and electric properties are investigated using powder X-ray diffraction(XRD), field emission scanning electron microscopy(FESEM), X-ray photoelectron spectrometer(XPS), Raman spectrometer, ultraviolet and visible spectrophotometer(UVVis), and a standard four-probe method. Cu In1-xCex Te2 crystallizes into a tetragonal structure with predominant orientation along the [112] direction. The lattice parameters are a = 6.190(6) ?A–6.193(0) ?A and c = 12.406(5) ?A–12.409(5) ?A. Ce prefers to occupy the 4b crystal position. According to the analysis of XPS spectra, Ce shows the mixture of valences 4+and 3+. Raman spectra reveal that the photon vibrating model in the CICT follows A1 mode in a wavenumber range of123 cm-1–128 cm-1. UV-Vis spectra show that the band gap Eg values before and after 0.1 mole Ce doped into Cu In Te2 are 1.28 e V and 1.16 e V, respectively. It might be due to the mixture of valences for Ce. Ce doped into Cu In Te2 still shows the semiconductor characteristics.
