Crystal structure and magnetism of Gd2MgGe2

Abstract

The title compound, Gd2MgGe2, crystallizes in a ternary variant of the tetragonal U3Si2 structure type with unit cell parameters of a=7.291(1) and c=4.2826(8) Angstrom, space group P4/mbm, Z=2. Temperature (4.3-300 K) and magnetic field (0-50 kOe) dependencies of the dc magnetization, along with temperature dependence of the ac magnetic susceptibility (25 Oe, 125 Hz) of Gd2MgGe2 are presented. The behavior of both the dc magnetization and ac magnetic susceptibility above ca. 150 K indicates a disordered magnetic state for Gd atoms while below ca. 150 K, it shows the existence of antiferromagnetic order. Tight-binding electronic structure (TB-LMTO-ASA) calculations including spin-polarization are utilized to discuss the chemical bonding and provide insights for the magnetic ordering process in this compound. (C) 2001 Elsevier Science B.V. All rights reserved.