New Ternary Boride EuRh4B4 Synthesized under High Pressure and Temperature

Abstract

We report the results of a detailed study of EuRh4B4 compound synthesized by an un-common method under high pressure temperature conditions for the first time. Synthesized sample has been initially characterized by X-ray diffraction, macroscopic electrical resistivity and ac-susceptibility methods. The ferromagnetic and superconducting phases were found below 83K and 5.8K respectively. Element-and shell-selective XANES and XMCD techniques have been further applied to check the possible valence transition of Eu ions and their magnetic states. XANES spectra recorded at the Eu L2,3 absorption edges clearly indicate the presence of either magnetic Eu2+ or non-magnetic Eu3+ ions in the sample. The XMCD studies have also shown that local magnetic moments of Eu2+ ions exist in the superconducting EuRh4B4, at least above the transition.