Experimental Study On Magnetic Properties Of Semiconductor In Doped SnO System

Spintronics,as a new field of physics,has laid a mature theoretical foundation for the combination of semiconductor and magnetism.With the wide application of spintronics,it has been found that Zn O,Sn O,Cu O and Ni O oxide semiconductors have weak magnetic properties.Among the tin oxides,Sn O₂ and Sn O have attracted much attention for their potential applications in photovoltaic devices such as solar cells,displays,photoelectric sensors and transparent thin film transistors.Most scholars have studied the conductivity of Sn O,and as another aspect of spintronics,the regulation mechanism of magnetism also needs to be further studied.In this paper,Cr and Mg doped Sn O were successfully prepared by one-step hydrothermal reaction method with simple operation and low cost.XRD,SEM,Raman technology,XPS and SQUID were used to conduct in-depth analysis of the prepared materials.Finally,the origin of magnetic and regulation mechanism of Sn O were proposed.At the hydrothermal temperature of 100?,Cr doped Sn O was successfully synthesized by hydrothermal method.XRD patterns confirmed that Cr ions had successfully entered the tin oxide lattice without magnetic aggregation,and the introduction of Cr ions caused lattice distortion through Cr _Sn and Cr_i at different positions of the lattice and affected the content of oxygen vacancy(V_O).Further studies of FESEM and TEM show that Cr doped Sn O has typical nanosheet structure.Uv-vis analysis showed that with the increase of Cr ion concentration,the bandgap of Cr doped Sn O first decreased and then increased.Both the pure and doped Sn O showed the characteristics of RTFM.We attributed the magnetic source of Sn O to V_Odefects,which could be regulated by Cr doping.We synthesized ferromagnetic Sn O nanoparticles with different Mg doping concentrations by hydrothermal method.SEM and TEM show that the micro units of Sn_1-xMg_xO prepared are nanospheres formed by interlacing irregular nanometer sheets.With the increase of Mg doping concentration,it can be seen that the basic irregular nanosheets gradually evolved into regular square sheets,and the interpenetration and aggregation of nanosheets gradually deteriorated significantly.Based on the test results of SEM and XPS,we know that with the increase of Mg doping concentration,the oxygen vacancy defect of Sn O decreases.Meanwhile,the increase of nanometer sheets effectively improves the air exposure opportunity of the material and absorbs more oxygen in the environment.With the increase of Mg doping concentration,we can see that the saturation magnetization of the material gradually decreases.We attribute the magnetism of pure Sn O to the intrinsic oxygen vacancy.Combined with the principle of indirect double exchange,a V_O can contribute two unpaired electrons and a large local state electron orbital,so that Sn²⁺spin can obtain a ferromagnetic ordered state and effectively regulate the magnetism.A series of excellent physical properties and manufacturing advantages of Cr and Mg doped Sn O make it a potentially valuable material in the field of spintronics.