Single Crystal Growth And Physical Properties Of New Eu-based Ternary Magnetic Compounds

Magnetic materials play a important role in the development of society because of their special properties.Nowadays,advanced magnetic functional materials such as permanent and soft magnetic materials and magnetoresistance materials are widely used in scientific research and social production.Among them,magnetic semiconductor has become a new generation of device application materials in spintronics because of its magnetic and semiconductor properties,which can process,transmit and store information more conveniently and efficiently.Eu-based compounds exhibit abundant magnetic mechanisms and occupy a large part of the known magnetic materials.In this paper,three Eu-based magnetic compound single crystals were grown and studied,which further enriched the content of the system.The related work mainly includes:1.Eu₃Sb₄Se₉ single crystal was grown by slow cooling method,and its structure and basic physical properties were studied by XRD,EDX and PPMS.The research results show that Eu₃Sb₄Se₉ crystal is a new pseudo-one-dimensional magnetic semiconductor.The ground state of Eu₃Sb₄Se₉ crystal is ferrimagnetic at low temperature,and there is a phase transition from ferrimagnetic to ferromagnetic at 2 T.Through the modified Arrott diagram to study the critical behavior of the sample,the transition temperature of T_c=5.1K was obtained,and the magnetic phase diagram of this material was made,and its magnetic structure was analyzed.2.Eu₄Bi₆Se₁₃ single crystal was grown by slow cooling method,and its structure and basic physical properties were studied.The magnetic test found that the Eu₄Bi₆Se₁₃crystal has antiferromagnetism,and the Neel temperature T_N=5.6 K.The electrical transport test found that the Eu₄Bi₆Se₁₃ crystal has metallic behavior,and there is a positive magnetoresistance phenomenon when an external magnetic field is applied.The main carriers are electrons,and the density is 6.403×10¹⁹ cm^-3.3.EuIn₂As₂crystals were grown by flux method,and the crystal structure and element ratio were determined.The magnetic test found that there may be an interaction of two magnetic mechanisms inside the EuIn₂As₂ crystal.The electrical transport test found that EuIn₂As₂ crystal has metallic behavior and negative magnetoresistance.The main carriers in the crystal are holes with a density of 3.44×10²⁰ cm^-3.