Eur. Phys. J. B 26, 273-289 (2002)
https://doi.org/10.1140/epjb/e20020090

Element-specific magnetic long- and short-range order and competing interactions in Gd_xEu_1-xS

¹ Institut für Festkörperphysik des Forschungszentrums Jülich, 52425 Jülich, Germany
² Northern Illinois University, Department of Physics, DeKalb, IL 60115, USA
³ Labor für Festkörperphysik, ETH Hönggerberg, 8093 Zürich, Switzerland
⁴ Institut Laue Langevin, BP 156, 38042 Grenoble Cedex 9, France
⁵ European Synchrotron Radiation Facility ESRF, BP 220, 38043 Grenoble Cedex 9, France

Corresponding author: ^a T.Brueckel@fz-juelich.de

Received: 25 April 2001
Revised: 3 December 2001
Published online: 15 April 2002

Abstract

We report on an investigation of the magnetic properties of Gd_xEu_1-xS mixed crystals with compositions in the range of 0.6<x<1. For the two samples Gd_0.8Eu_0.2S and Gd_0.73Eu_0.27S a long-range antiferromagnetic order was observed at low temperatures. Element-specific measurements exhibited a different temperature dependence of the reduced sublattice magnetisation of the two magnetic species. A model calculation and Monte Carlo simulations revealed that the different temperature dependence is due to frustration effects. These frustration effects lead to a breakdown of the long-range order for higher europium contents. For the Gd_0.67Eu_0.33S-sample we were able to observe a short-range antiferromagnetic order with correlation lengths of a few 10 Å with X-ray resonance exchange scattering.