Electronic states of the constituent magnetic elements, superior magnetic properties and spin-flip metamagnetic transition in Cu3Dy(SeO3)2O2Cl

Dy based cuprate francisite [Cu ₃Dy(SeO ₃) ₂O ₂Cl, in short DyCufr] is so far potentially the most fascinating magnetic compound in the class of francisite compounds. Synthesized DyCufr has been investigated via structural, X-ray absorption near edge structure (XANES), X-ray photoelectron spectroscopy (XPS) and magnetization measurements. XANES and XPS provide consistent and corroborative results regarding electronic states of the constituent elements. The most striking observation is that the slope of magnetization for the field induced metamagnetic transition (MMT) attains nearly infinity (perfect), hysteresis associated with MMT is substantially high, and the critical field for MMT is very low. The antiferromagnetic ordering temperature ( T N ), saturation magnetization ( M S ) are very high, and the remanent magnetization ( M R ) is appreciable in DyCufr in contrast to few other similar compounds. Unpaired 4f electrons of Dy ³⁺ causing high value of effective magnetic moment and spin-flip type metamagnetism are pivotal for producing magnetically the most superior francisite. Actually, sharp MMT as evidenced in DyCufr, has the potential to be used in magneto-refrigeration and spin-electronic devices because it can produce an avalanche flip of spin structure from low-spin (antiferromagnetic) to high-spin (ferromagnetic) state.