Preparation And Dielectric Properties Of Lutetium Ferrite

Multiferroic materials with abundant physical capabilities have broad application prospects in industrial production,especially in the fields of information storage,spintronics and sensors.The coupling effect of order parameters enables mutual tuning between various properties,which further enriches the physical properties of multiferroic materials.The thesis systematically discusses the preparation method of LuFe2O4 ferrite material,and studies its dielectric properties and microwave absorption.The sol-gel method is used to prepare LuFe2O4 multiferroic materials,and the raw material ratio of Lu and Fe,the gas atmosphere during annealing,the annealing temperature and the oxygen partial pressure are explored.The experimental products of 1:2 raw material annealed in argon at 1200? for 300 min is a single-phase LuFe2O4.The preparation steps of the sol-gel method are easy to control,and provide an experimental basis for the subsequent element substitution and film preparation for LuFe2O4.The dielectric response of LuFe2O4 material to the bias voltage in the band below 3 KHz is studied,and it is found that its dielectric constant decreases continuously with the increase of the bias voltage.Magnetic properties tests show that the transition temperature(TN)of LuFe2O4 multiferroic materials from paramagnetic phase to ferromagnetic phase is about 240 k.In order to investigate the microwave absorption performance in the 2-18 GHz band,the dielectric constant(?r),complex magnetic permeability(?r),attenuation coefficient(a),wave impedance coefficient(M?),input impedance coefficient(Mz)and reflection loss(RL)of LuFe2O4 were discussed in detail.It is found that the effective absorption bandwidth(RL?-10 dB)is up to 4.24 GHz at a thickness of 1.5 mm and a minimum reflection loss is up to-33.95 GHz at a thickness of 2 mm.Therefore,LuFe2O4 multiferroic materials can achieve broadband microwave absorption at a small thickness,and are expected to be widely used in the field of electromagnetic wave stealth materials.