Magnetism And Spin Switching Of Single Crystal Rare-earth Perovskites Er_1-x?Y?Pr?_xFeO₃

Since the 1960s,researches on various physical properties of orthoferrites RFeO₃?Rare earth,R=Y,La-Lu?have been carried out continuously,covering many research fields such as magnetic structure and magnetization behavior,magnetoelectric coupling effect,magneto-optical interaction etc.In recent years,it has attracted much attention to the regulation of physical properties such as spin reorientation transition and spin switching effect.Therefore,it is of great significance to analyze the physical mechanism and explore the possible application prospect.In this paper,we introduce the research overview of the orthoferrites RFeO₃,crystal structure and magnetic structure,as well as the important characteristics of RFeO₃ system:spin reorientation phase transition and spin switching effect.1)The Er_1-xY_xFeO₃?x=0,0.25,0.5,0.75,1?and Er_1-xPr_xFeO₃?x=0.1,0.3,0.5?single crystal family are successfully prepared.We have introduced the experimental methods involved in this work,including the preparation of polycrystalline samples by solid phase reaction method,the preparation of single crystal samples by optical floating zone method,structural characterization methods and physical property measurement methods.Following,we will discuss the influence of the non-magnetic Y³⁺and magnetic Pr³⁺doping in the magnetization behavior of ErFeO₃.The spin orientation phase transition and the spin switching of the system doped with two ions are focused as below.2)The preparation and magnetic properties of Er_1-xY_xFeO₃?x=0.25,0.5,0.75,1?single crystal family are systematically studied.The Rietveld structure is refined on the X-ray diffraction data of the Er_1-xY_xFeO₃ single crystal family,and the change of the unit cell parameters with the rare earth doping is obtained.By doping non-magnetic Y³⁺,we have tuned the spin reorientation temperature to low temperature with increasing x.The variation of compensation point and spin switching point with doping amount are also discussed.The interaction between the rare earth ion sub-lattice and the iron ion sub-lattice is analyzed.The experimental results show that the spin reorientation temperature range,the compensation point and the temperature point of the spin switching change with the doping amount.Regularity,the interaction between rare earth ion sub-lattice and iron ion sub-lattice is analyzed.3)Secondly,by preparing high quality Er_1-xPr_xFeO₃?x=0.1,0.3,0.5?single crystal family and measuring physical property,the magnetic moments of three magnetic ions(Er³⁺,Pr ³⁺,Fe ³⁺)in this doped system is analyzed.It is observed that there is still?₄?G_x,A_y,F_z?to?₂?F_x,C_y,G_z?spin reorientation after Pr³⁺doping.Pr³⁺play an important role that pushes the spin reorientation temperature range toward high temperature,but excessive Pr³⁺doping will inhibit the occurrence of spin reorientation.4)Finally,a variety of spin switching effect in the RFeO₃ system is classified and discussed.We have analyzed the specific conditions of spin switching of different rare earth ionic compounds.The magnetic configuration of rare earth ion and iron ion during the phenomena are discussed in detail and the classification method of spin switching is proposed.Moreover,we have discussed the regulation of the external magnetic field on spin switching.