Local lattice distortions and magnetic properties of CdCr2Se4-xSx

Abstract

Interplay between structural disorder and magnetic interaction is investigated here for a multiferroic candidate material, CdCr2Se4. Ferromagnetic order in CdCr2Se4 sets in below TC ∼ 130 K as a result of competition between the direct Cr-Cr spin coupling and the near neighbour Cr-Se-Cr exchange interactions. Hence, a small change in the crystal structure is expected to drastically affect its magnetic order. In this report, local lattice distortions within the overall cubic symmetry were brought about by replacing a small percentage of Se by isovalent S. Detailed crystal structure study using EXAFS and Raman Spectroscopy reflects the presence of local distortions within the overall cubic symmetry. Contrary to the expectation, magnetic properties of the substituted compositions do not show any drastic changes. Though, a signature of spin-phonon coupling is present across the magnetic ordering temperature. No structural phase transition occurs within the investigated temperature range of 80-300 K. © 2016 Author(s).