Solvothermal synthesis of Cr-doped MS(M=Zn, Cd) nanostructures with room-temperature ferromagnetic property

Abstract

Using ethanolamine (EA), ethylene glycol (EG) and ethylenediamine (EN) as mixed solvents, MS (m = Zn, Cd) semiconductor nanostructures doped with different amounts of chromium were successfully prepared in different S, Zn and Cd sources by simple solvent thermal method. X-ray diffraction (XRD) measurements showed that the nanostructure MS (M = Zn, Cd) had wurtzite structure. Scanning electron microscopy (SEM) images showed the morphology of MS (M = Zn, Cd) with different chromium content. Energy dispersive spectrometer (EDS) was used to observe that the product was composed of Cr, Zn, Cd, and S. Vibration sample magnetometer (VSM) measurements showed that ZnS doped with chromium exhibited ferromagnetism at room temperature, while the undoped ZnS exhibited diamagnetism at room temperature.The spontaneous magnetization Ms of chromium-doped ZnS (Cr = 5.41 at%, 8.25 at%) nanosheets are about 2.583 and 5.874 (10−3emu/g), respectively. The coercivity of Hc is about 55.670 and 89.721 Oe. The ferromagnetism of pure CdS was weak, while that of Cr-doped CdS was enhanced at room temperature. The spontaneous magnetization Ms of Cr = 0, 1.75 at% and 2.03 at% nanosheets are 0.994, 2.866 and 8.655 (10−3 emu/g), respectively. The coercivity of Hc is about 75.623, 115.431 and 65.358 Oe. The ferromagnetism of Cr-doped ZnS at room temperature is confirmed by the experimental results, which is consistent with the ferromagnetism of Cr-doped ZnS calculated by the first principle. The origin of ferromagnetism of Cr-doped CdS is related to the substitution of Cr in CdS lattice.