Synthesis of Cr-doped ZnO diluted magnetic semiconductor by hydrothermal method under pulsed magnetic field

In this study, zinc chloride, chromic chloride, ammonium hydroxide and ammonium chloride are used as the source materials to prepare the crystalline Cr-doped ZnO diluted magnetic semiconductor by the hydrothermal method under a 4-T pulsed magnetic field. The structures and the morphologies of the samples are characterized by X-ray diffraction and scanning electron microscope. The magnetic analysis of the specimens is performed by vibrating sample magnetometer. The effects of pulsed magnetic field on the microstructure and the magnetic properties of the Cr-doped ZnO are discussed. The result indicates that all the samples still have hexagonal wurtzite structures. The pulsed magnetic field is conducive to promote the crystal growth orientation. The sample fabricated under pulsed magnetic field exhibits good room temperature ferromagnetism. The saturation magnetization is 0.068 emu/g. However, the sample synthesized without magnetic field shows paramagnetism at room temperature. The Curie temperature (Tc) of the Cr-doped ZnO is increased by 16 K through the pulsed magnetic field processing.