Cu and Fe valence states in CuFeS2

Mossbauer effect (MES), X-ray photoelectron (XPS) spectroscopies were used to study antiferromagnetic CuFeS2, especially its Cu and Fe ground-state properties. Pressure- and temperature-dependent MES results show that Fe 31 is high-spin. The low isomer shift is constant with pressure, and consistent with strong FeS covalency, not with mixed valency. XPS results indicate that the Cu ion is 1(+) (3d(10)). For "ideal" CuFeS2 we extrapolate a hyperfine field of 363 kOe, large enough for Fe3+ to be high-spin. (C) 2003 Elsevier B.V. All rights reserved