Spinlattice coupling studied by magnetic entropy and EPR in the CdCr _2S_4 system

摘要

The magnetic entropy around the paramagneticferromagnetic (PMFM) phase transition temperature TC has been investigated for chromium based spinel CdCr_2Se_4. It is found that magnetic entropy changes are generated by the spinlattice coupling, which can be easily modulated by the external magnetic field. The electron paramagnetic resonance (EPR) study proves the existence of the spinlattice coupling above TC, and reveals the stronger coupling at TC. In addition, the variation of the micro-structure due to the spinlattice interaction has been observed around TC from the measurement of the low-temperature X-ray diffraction.