Magnetization and Intrinsic Coercivity for τ-phase Mn₅₄Al₄₆/α-phase Fe₆₅Co₃₅Composite

We have synthesized ferromagnetic ${\tau}$-phase $Mn₅₄Al₄₆/{\alpha}$-phase $Fe₆₅Co₃₅$ composite by annealing a mixture of paramagnetic ${\varepsilon}$-phase $Mn₅₄Al₄₆$ and ferromagnetic ${\alpha}$-phase $Fe₆₅Co₃₅$ particles at $650^\circC$. The volume fraction ($f_h$) of hard ${\tau}$-phase $Mn₅₄Al₄₆$ of the composite was varied from 0 to 1. During the annealing, magnetic phase transformation occurred from paramagnetic ${\varepsilon}$-phase to ferromagnetic ${\tau}$-phase $Mn₅₄Al₄₆$. The magnetization and coercivity of the composite monotonically decreased and increased, respectively, as the $f_h$ increased. These results are in good agreement with our proposed composition dependent coercivity and modified magnetization equations.