Mixed valence and metamagnetism in a metal flux grown compound Eu2Pt3Si5

Abstract

A new compound Eu2Pt3Si5 with plate shaped morphology has been grown from excess In flux. The compound crystallizes in the orthorhombic U2CO3Si5 structure type, 1bam space group and the lattice parameters are a=10.007(2) angstrom, b=11.666(2) angstrom and c=6.0011(12) angstrom. The crystal structure of this compound can be conceived as inter-twinned chains of [Pt2Si2] and [PtSi3] tetrahedra connected along [100] direction to give rise to a complex three dimensional [Pt3Si5] network. Temperature dependent magnetic susceptibility data suggests that Eu2Pt3Si5 undergoes a strong antiferromagnetic ordering (T-N=19 K) followed by a weak ferromagnetic transition (T-C=5.5 K). The effective magnetic moment/Eu obtained from susceptibility data is 6.78 mu B accounts mixed valent Eu with almost 85% divalent Eu, which is supported by X-ray absorption near edge spectroscopy. The compound undergoes a metamagnetic transition under applied magnetic field through a probable spin flop mechanism. (C) 2015 Elsevier Inc. All rights reserved.