Spin glass anomalies in HP-NdPtSn - structural, magnetic and specific heat studies

摘要

The hexagonal high-pressure (HP) modification of NdPtSn was prepared under multianvil high-pressure (10.5 GPa) high-temperature (1425 K) conditions from the orthorhombic normal-pressure (NP) modification. NP- and HP-NdPtSn were studied by X-ray powder and single crystal diffraction: TiNiSi type, Pnma, a = 737.2(1), b = 460.0(1), c = 799.6(2) pm, wR2 = 0.0662, 441 F-2 values, 20 variable parameters for NP-NdPtSn, and ZrNiAl type, P6 (2) over barm, a = 753.55(5), c = 410.55(4) pm, wR2 = 0.0709, 248 F2 values, 14 variable parameters for HP-NdPtSn. Temperature dependent susceptibility measurements reveal paramagnetism for HP-NdPtSn above 20 K with an experimental magnetic moment of 3.73(2) mu(B)/Nd mol and a paramagnetic Curie temperature theta(P) of -5(1) K. The low-temperature data indicate spin glass behavior with a freezing temperature around 4.5 K. The spin glass anomalies are also evident from specific heat measurements. (c) 2006 Elsevier Masson SAS. All rights reserved.