Research of Structure and Magnetic Properties of Yttrium-doped M-type Strontium Ferrite

Yttrium-doped M-type strontium ferrite SrYxFe(12-x)O19(x=0,0.25,0.5,0.75,1.0)calcined materials were prepared by solid-phase sintering method at 1150℃for 3h.Then the calcined materials were pressed for magnets under the condition of oriented magnetic field and sintered at 1295℃for 3h.X-ray diffraction,scanning electron microscope and magnetic tester were used to analyze the phase structure of the sintered magnets,the surface morphology of the sintered magnet and the magnetic properties of the sintered magnets respectively.The results showed that with the increase of yttrium-doped,the lattice constant achanges little,cincreases slowly,a/c first increases and then decreases,crystal X-ray density dX-rayapproximation increases linearly.SEM showed that the magnet has prepared a typical hexagonal structure morphology.Magnetic studies showed that with the doping of yttrium increase,the remanence Brincreasing monotonically,intrinsic coercivity Hcjand maximum energy product(BH)maxand coercivity magnetic induction Hcbfirst increasesd and then decreased.When x=1.0,the remanence Brreach maximum with 420.7mT,but the intrinsic coercivity Hcjdecreased to a minimum value;when x=0.75,the intrinsic coercivity Hcjhave a maximum value of 323.7kA ·m-1,and the remanence Brreached 410.4mT.