The study on abnormal temperature characteristics of coercivity in Alnico 8 alloys

•The abnormal Hc rapidly increases with the rising temperature from 30 °C to 240 °C.•The a1 is the finite-nonlinear-dispersed magnetic nanoarray in spatial distribution.•The abnormal Hc originates from the improved magnetization reversal model.•The magnetization reversal model is nearly steady from 240 °C to 400 °C.