Abstract:
Sr1-xLaxFe12O19 (x=0, 0.05, 0.1 and 0.15) ceramics were successfully synthesized by solid state reaction method. La doping can affect the crystal lattice parameters, but it has little effect on the morphology. The dielectric constant of the doped ceramics is significantly higher than that of the pure phase ceramics, but the dielectric loss is relatively large. The dielectric properties of the doped ceramics are mainly caused by the Maxwell-Wagner interface polarization effect. At the same time, the magnetic properties are improved after doping lanthanum ions. The change of the dielectric constant with magnetic field shows that the temperature transition from positive to negative magnetodielectric effect is different. The transition temperature for the pure SrFe12O19 is between 50 and 75 K, and the transition temperature for samples with x=0.05, 0.1 and 0.15 is between 25 and 50 K. The magnetodielectric coefficient is relatively large between 75 and 200 K due to the polarization effect of the Maxwell-Wagner interface, which is an extrinsic phenomenon.The results show that the dielectric constant of La doped ceramics is greatly improved, while the magnetic properties are well maintained.
