Preparation,Magnetic And Electrical Properties Of Y₃Fe₅O₁₂ Nanofibers

Spintronic devices based on yttrium iron garnet(Y₃Fe₅O₁₂,YIG)can use electron spin as a carrier for information transfer due to the low magnetic damping and long spin transport distance of YIG,which brings new hope for breaking through the process limitations of the charge properties of electrons and has a broad application prospect in the field of future integrated circuits.However,the study of one-dimensional YIG nanofiber devices is still a challenge at present.In this paper,the electrical,magnetic and magnetoelectric properties of single YIG nanofibers prepared by electrospinning method are investigated at different temperatures,and their conductive mechanisms are discussed in detail,and corresponding physical models are proposed to explain their generation mechanisms.The main research works of this paper are as follows.1.The effect of spinning process parameters on the morphology of YIG nanofibers was systematically investigated by varying the spinning voltage,polymer concentration,ion concentration and annealing temperature.The influence of the annealing process on the pure phase preparation of YIG nanofibers was investigated by varying the annealing temperature,holding time and yttrium-iron ion ratio to achieve controlled preparation of YIG nanofibers.2.Single YIG nanofibers were prepared by electrospinning on Si substrate,and single YIG nanofiber devices were prepared by focused ion beam.The single YIG nanofibers exhibit non-ohmic conductivity at low temperatures and ohmic conductivity at high temperatures with a transition temperature of 160 K.A grain-grain boundary model is proposed to explain this phenomenon in the single YIG nanofibers.The results of fitting the grain and grain boundary to the Variable Range Hopping model and Simmons model indicate that the non-ohmic conductivity is caused by the tunneling of the grain boundary in the nanofibers.3.The results of magnetoresistance measured at different temperatures show that the magnetoresistance of YIG nanofibers increases and then decreases with increasing temperature,and a maximum value of 6.6%occurs at a temperature of 50 K.Combined with the magnetic tests of YIG nanofibers,a model of intergranular tunneling magnetoresistance is proposed.The results show that the magnetoresistance of single YIG nanofibers is mainly influenced by the grain-to-grain tunneling magnetoresistance.