Sintering temperature optimization for enhanced magnetic performance in La–Ca–Co doped strontium ferrite

The effectiveness of employing La-Ca-Co co-doping has been demonstrated as the optimal approach for enhancing the magnetic performance of strontium ferrite. However, limited studies have explored the evolution of the magnetoplumbite phase and its correlation with the sintering temperature. In our research, La-Ca-Co doped strontium ferrite permanent magnets were fabricated using a conventional ceramic process and a two-step sintering technique. After sintering at different temperatures, all the samples possess proper c-axis orientation. When the sintering temperature was raised from 1175 °C to 1205 °C, there was an upward trend observed in the remanence Br, increasing from 430 mT to 439 mT. The coercivity Hcj exhibited an increase from 380 kA/m and reached its peak at 397 kA/m at 1185 °C. Although the Br value remained favorable, the coercivity experienced substantial deterioration, reaching its lowest point at 303 kA/m at 1205 °C. Under a sintering temperature of 1195 oC, magnetic performance with optimal energy product was achieved, with Br of 439 mT, Hcj of 379 kA/m, Hcb of 318 kA/m, and (BH)max of 35.5 kJm-3.