Study Of Magnetism In Multiple Oxides Controlled By Electric Field

Magnetic materials have been the interest of many researchers for many years since magnetic materials have great research and application value in the fields of electricity,magnetism,optics and mechanics.Magnetic materials play an important role in human life and production activities,which can be widely used in communication industry,transportation industry,information storage industry,microwave components and so on.Recently,nano-magnetic materials have aroused great interest among researchers.When the size of the material reaches the nanometer scale,abnormal magnetic properties and electrical properties will appear.It is because of quantum size effect and interface effect.Nano-materials can show a completely different magnetic properties from traditional magnetic materials,which can be used to modify traditional materials and produce high-tech nano new products.On this basis,we can realize magnetic materials applicate in the electron spin devices and information storage of low power consumption by electric field controlling magnetism.Because of its tremendous research potential and research value,scientists have paid more and more attention in recent years.For some multiferroic materials in which ferromagnetism and ferroelectricity coexist,we can realize the regulation of magnetism by electric field,or the regulation of electrical property by magnetic field due to their unique magnetic-electric coupling characteristics.In the heterostructure of ferromagnetic/ferroelectric structures,strong magnetic coupling can also occur.The ferroelectric phase can be stressed by the electric field,which cause a change in ferromagnetic phase magnetism.With the development of the semiconductor industry,Non-volatile Resistive Random Access Memory attracted the attention of the researchers more and more because of its low energy consumption,high density,high speed and high information retention.IGZO is a transparent semiconductor oxide,characterized by relatively simple production process,high performance,higher mobility and better stability.Prior to this,many people have studied the resistance switching properties of the amorphous IGZO thin film device,but no one has studied the relationship between resistance switching and their magnetic transformation.Summarizing,this thesis has carried on the research of the following several content mainly:GdFeO3 polycrystalline powder samples were prepared by sol-gel method.For the first time,we find that when the grain size was at the nanometer scale,the polycrystalline GdFeO3 sample showed the phenomenon of compensation temperature near room temperature.The compensation temperature of the sample is closely related to the external magnetic field intensity,annealing temperature and Gd/Fe ratio.On this basis,We prepared Gd1-xSmxFeO3(x=0.1,0.3,0.5)with solid phase sintering method.We can realized the regulation of the remanent magnetization by applying electric fied,but the regulatory effect is not ideal.Gd3-xYxFeOO12(x=0,0.3,0.9,1.5)polycrystalline samples were prepared by sol-gel method,and studied the influence of external magnetic field and Y doping ratio on the compensation temperature of Gd3Fe5O12.It is found that with the increase of Y doping proportion,the compensation temperature of Gd3Fe5O12 is moving in the low temperature direction.We find that applying electric field could regulate the magnetization and remanent magnetization of Gd3-xYxFe5O12(x=0,0.3,0.9)sintered plate.Under the applied electric field,both magnetization and magnetic remanence decrease below the compensation or valley temperature,but increase above the compensation or valley temperature.The magnitude of remanence change increases with electric voltage,but remains the same when the only direction of electric voltage is reversed.The Ag/amorphous InGaZn04/Pt resistance switching storage device was prepared by RF magnetron sputtering.We studied the resistance switching properties of the Ag/a-IGZO/Pt device by applying a scanning electric field to resistors,and measured the magnetism of the device in high resistance state(HRS)and low resistance state(LRS).Through the study,we found that the resistance switching of the device is caused by the Ag conductive filament mechanism.The magnetization intensity when the device is in the high resistance state is less than that when the device is in the low resistance state.