Study On The Preparation And Magnetic Performance Of Rare Earths Substituted M-type Strontium Ferrite Sr_1–xLn_xFe_12–xM_xO₁₉?Ln:Yb,Gd?M:Co,Zn?

M-type strontium ferrite(SrFe12O19)is an important permanent magnet material,because it has good chemical stability and anti-demagnetization,and a wide range of resources,low price,mature preparation process,so it is widely used in high density magnetic materials,magnetic fluid,microwave devices and other fields.The magnetic properties of strontium ferrite are obviously lower than those of Nd2Fe17 B ferrite.Therefore,how to improve the magnetic properties of M-type strontium ferrite materials has become the main research target in China.In this paper,the hexagonal strontium ferrites Sr1–x Lnx Fe12–x Mx O19(Ln: Yb,Gd?M: Co,Zn;x = 0,0.05,0.1,0.15,0.2)were doped with equivalent ions were prepared by the chemical co-precipitation method.X-ray diffraction(XRD),scanning electron microscopy(SEM)and vibrating sample magnetometer(VSM)were employed to analyze the phase structure,morphology and magnetic performance,respectively.The results show that:1.M-type strontium ferrite Sr1-x Ybx Fe12-x Cox O19(x = 0,0.05,0.1,0.15,0.2)were co-doped with equivalent Yb-Co ions: When the doping amount of 0 ? x ? 0.1,the synthesized product is single phase M-type strontium ferrite.When x > 0.1,the phase of ?-Fe2O3 and Co Fe2O4 appeared in the sample,and most of the grain is six angle flake structure.When the Yb-Co doping amount is x = 0.1,the saturation magnetization(Ms),remanent magnetization(Mr)and coercive force(Hc)of strontium ferrite Sr0.9Yb0.1Fe11.9Co0.1O19 reach to the maximum values of60.89 emu/g,31.96 emu/g and 6846 Oe,respectively.2.M-type strontium ferrite Sr1-x Ybx Fe12-x Znx O19(x = 0,0.05,0.1,0.15,0.2)were co-doped with equivalent Yb-Zn ions: When the doping amount of 0 ? x ? 0.1,the formed strontium ferrite is a single M-type six square crystal phase.When x > 0.1,the ?-Fe2O3 impurity phase is produced in the sample.Most of the grain is six angle flake structure.When the amount of dopant of Yb-Zn is x = 0.1,the magnetic properties of strontium ferrite appear to be maximum value.That means Ms = 66.75emu/g,Mr = 30.77 emu/g and Hc = 5915 Oe,respectively.3.Gd-Co ions replacement of M-type strontium ferrite Sr1-x Gdx Fe12-x Cox O19(x=0,0.05,0.1,0.15,0.2): When the doping amount is 0 ? x ? 0.1,the sample is a single M-type strontium ferrite.When the amount of doping x > 0.1,the samples appear a variety of impurities such as ?-Fe2O3,Gd Fe O3,Gd Fe2O4 and so on.Most of the grain is six angle flake structure.The strontium ferrite Sr0.9Gd0.1Fe11.9Co0.1O19 wasdoped by Gd-Co ions,its magnetic properties reached maximum value.That is Ms = 44.20 emu/g,Mr = 26.74 emu/g and Hc = 5058 Oe,respectively.4.Gd-Zn ions replacement of M-type strontium ferrite Sr1-x Gdx Fe12-x Znx O19(x=0,0.05,0.1,0.15,0.2): When the doping amount of x is less than 0.05,the morphology of the sample is a single M-type six square crystal phase.When x > 0.05,the ?-Fe2O3 impurity phase is produced in the sample.Most of the grain is six angle flake structure.When the amount of dopant of Gd-Zn is x = 0.05,the maximum magnetic properties appeared.It is Ms = 49.82 emu/g,Mr = 30.92 emu/g,and Hc = 5384 Oe,respectively.