Preparation Of Sm/Gd-Cu Substituted M-type Strontium Ferrites And Their Magnetic Performances

The ferrite material has great magnetic,superior chemical stability and excellent corrosion resistance.Since it was found in mid of the last century,due to excellent performance has been attracting the attention of researchers both at home and abroad.Especially the strontium ferrite,barium ferrite,more researchers interested in the cause.With the development of informatization,magnetic materials because of its great comprehensive performance,simple preparation technology and low cost.so it can referred to as magnetic storage materials,microwave absorbing materials,electrical components and permanent magnets,etc.In addition,in recent years,ferrite can be used in catalysis and magnetic media,so strontium ferrite urgent to develop magnetic materials with better performance.First we prepared Sm³⁺/Gd³⁺and Cu²⁺ ions joint replaces the Sr²⁺ and Fe³⁺ ions in strontium ferrite by solid phase method.When Sm/Gd-Cu doping amount 0?x?0.2,the single-phase of M-type Sr_1-x?Sm/Gd?_xFe_12-xCu_xO₁₉ strontium ferrite has synthesized;And in low Sm/Gd-Cu doping amount,the magnets were found typical hexagonal block structure.By VSM test and analysis,draw a concluded that when the Sm-Cu doping amount x=0.10,raises the saturation magnetization Ms to a maximum value of 51.757 emu/g;suitable Gd-Cu substitution with x=0.05 raises the saturation magnetization to a maximum value of 51.253 emu/g.The coercive force of Sm/Gd-Cu substituted M-type strontium ferrite sample first increases then decreases with the increasing of the substituted amount,and the coercive force of Sm-Cu doped sample get a maximum of 809.904 Oe while the substituted amount x=0.1.However,the coercive force get a maximum value 565.495 Oe while the substituted amount x=0.05 of Gd-Cu substituted M-type strontium ferrite sample.The value of coercive force between the two appears relatively large gap.When the Sm-Cu doping amountx =0.05,remanence Br reach the maximum value?Mr?max=24.173 emu/g;When Gd-Cu doping amount x=0.05,the remanence Br reach the maximum value?Mr?max=27.673 emu/g.Second,we prepared Sm³⁺/Gd³⁺and Cu²⁺ ions joint to replace of strontium ferrite Sr²⁺ and Fe³⁺ ions by chemical co-precipitation.When Gd-Cu doping amount0?x?0.2,we have been synthesized by single phase of M-type strontium ferrite.Through scanning electron microscopy SEM,it can be found that the magnetic crystals in the magnets exhibit typical hexagonal corner or block structures.By VSM analysis we can found that the saturation magnetization Ms co-precipitation preparation of Sm-Cu doped strontium ferrite increased with the increase of doping amount increases,when the Sm-Cu doping amount x= 0.20,the saturation magnetization Ms reach to maximum 57.42 emu/g;However the saturation magnetization Ms of Gd-Cu doped strontium ferrite by chemical Co-precipitation synthesised first increases then decreases with the increasing of substituted amount,and when the amount of Gd-Cu doped x= 0.1,the saturation magnetization Ms reach to maximum value 56.25 emu/g.when the amount of Sm-Cu doped x=0.1,the Coercivity reached the maximum value of Hc=6862.60 Oe,and when the amount of Sm-Cu doped x=0.1 the coercivity reached the maximum value of Hc=7297.124 Oe.And with the increase of the doping amount,the coercive force Hc appears to increase first and then decrease.