Crystal structure, thermal expansion and magnetic properties of new compound Dy1.2Fe4Si9.8

The new ternary compound Dy1.2Fe4Si9.8 have been prepared and studied by means of X-ray powder diffraction technique and vibrating sample magnetometer. The ternary compound Dy1.2Fe4Si9.8 crystallizes in the hexagonal Er1.2Fe4Si9.8-type structure, space group P6(3)/mmc (no. 194) with lattice parameters a = 0.39415(1) nm and c = 1.52771(3) nm. The crystal structural refinement of the compound Dy1.2Fe4Si9.8 has been performed by using Rietveld method. Lattice thermal expansion studies on the compound were carried out in the temperature range from 298 to 1013 K. The variation of the unit cell parameters shows that the unit cell parameters increase with the increase in temperature. The coefficients of average lattice thermal expansion along various axes in the temperature range from 298 to 1013 K are alpha(a) = 1.42 x 10(-5) K-1, alpha(b) = 9.17 x 10(-6) K-1 and alpha(v) = 3.78 x 10(-5) K-1. The temperature dependence of the magnetization for the compound was also investigated in the range from 90 to 300 K. The experimentally determined magnetic effective paramagnetic moment is mu(eff) = 11.3 mu(B) per formula unit (10.3 mu(B) per Dy atom). (c) 2007 Elsevier B.V. All rights reserved.