Ding-Bang Xiong

Giant magnetocaloric effect in ε-(Mn0.83Fe0.17)3.25Ge antiferromagnet

The magnetic phase transition and magnetocaloric effect are investigated on e-(Mn0.83Fe0.17)3.25Ge compound. A large positive magnetic entropy change ΔSM is observed, which is accompanied with a field-induced metamagnetic transition from a collinear to a triangular antiferromagnetic configuration in this antiferromagnetic compound. The maximum value of ΔSM is 11.6J∕kgK at 93K for a magnetic field change of 7T. The study on systems with antiferromagnetic phases may open an important field in searching new materials for magnetic refrigeration.

Luminescence properties of CaZr(PO4)2:RE (RE = Eu3+, Tb3+, Tm3+) under x-ray and VUV–UV excitation

Novel phosphors of Eu3+, Tb3+ and Tm3+ doped CaZr(PO4)2 were synthesized by solid-state reactions and their x-ray and vacuum ultraviolet–ultraviolet (VUV–UV) spectroscopic properties were investigated. The bands near 147 or 185 nm in the VUV excitation spectra of those doped samples are attributed to the PO4 absorption and O to Zr charge transfer transition in the host. The excitation and emission spectra indicate that the phosphors can be effectively excited by x-ray or 147 nm and 172 nm and exhibit a satisfactory red, green and blue light performance, respectively. Considering the high luminescent intensity, excellent colour purity and chemical stability, CaZr(PO4)2:RE (RE = Eu3+ Tb3+, Tm3+) are attractive red, green and blue emitting x-ray and plasma display panel phosphors.