Pressure effects on spin-lattice coupling of CdCr2S4

Results of DC magnetization and x-ray diffraction measurements under hydrostatic pressure are reported for the CdCr2S4 spinel compound. Magnetization measurements were performed in a polycrystalline sample up to 14 kbar in the 20-220 K temperature range. At low applied magnetic fields an anomalous susceptibility behavior, associated to magnetic clusters, persists up to 14 kbar. X-ray synchrotron diffraction spectra acquired under pressure show a strong linear correlation between the variation of lattice parameters under pressure and the variation of the Cr-Cr distance. In contrast, the S-Cr-S angles remain constant. Clearly, the CdCr2S4 magnetic properties are strongly sensitive to pressure variations and the Cr local distortions observed in this compound promote a competition between direct antiferromagnetic and super-exchange ferromagnetic interactions within such short-range magnetic clusters.