¹⁵¹Eu-Mossbauer study of complex magnetism in Eu₂PdSi₃: effect of Eu²⁺ substitution by Y³⁺ and of high pressure

Abstract

With ¹⁵¹Eu-Mossbauer spectroscopy and other methods the complex magnetic properties of Eu₂PdSi₃, arising from the two crystallographically different lattice sites of the Eu²⁺ ions, have been already studied. Here we study the impact of magnetic dilution of the magnetic Eu²⁺ sites by non-magnetic Y³⁺ ions. A previous specific heat study has found reduced magnetic ordering temperatures with strong indication of disorder effects like in magnetic spin glasses. Here we provide from ¹⁵¹Eu-Mossbauer spectroscopy detailed information of the impact of Y³⁺ substitution on the magnetic properties of the two lattice sites, well distinguishable in the ¹⁵¹Eu-spectra. Since the substitution of the larger Eu²⁺ ions by the smaller Y³⁺ ions is connected with a lattice contraction, we also applied high pressure to the Eu₂PdSi₃ sample and observed drastic changes in the magnetic properties originating from a valence transition towards Eu³⁺ for one of the Eu sites.