Abstract
An experiment was carried out to investigate the effect of addition of composite rare-earth oxide (55La2O3-34Nd2O3-10Pr6O11) on magnetic properties of isotropic BaO⋅6Fe2O3 magnets. It was found that the magnetoplumbite structure was stabilized by addition of composite rare-earth oxide to BaO⋅6Fe2O3 compound. These Ba-La-Nd-Pr system ferrites had excellent properties as a isotropic parmanent magnet, and the value of (BH)max at the condition semisintered at 1000°C was equivalent to those of ordinary isotropic Ba and Sr ferrites, The optimum conditions of making an isotropic magnet and some properties of typical sample are as follows; a) composition: BaO⋅6Fe2O3 in addition with 2 wt% composite rare-earth oxide, b) semisintering condition: 1200°C×1h in O2 gas and sintering condition: 1350°C×0.5h in O2 gas, c) magnetic properties: Jm =0.395T, Jr=0.265 T, HcJ=184 kA/m, HcB=162 kA/m, (BH)max=11.8 kJ/m3, Tc=451°C, D=5.16 Mg/m3.
