A phenomenological description of the first-order transition in the Gd₅(Si_xGe_1−x)₄(0.24≤x≤0.5) alloys

With the help of the Landau–Devonshire theory, in this paper we produce a good phenomenological description of the first-order magnetocrystalline transition that occurs in the Gd₅(Si_xGe_1−x)₄(0.24≤x≤0.5) alloys, and derive the magnetic phase diagram in a magnetic field versus temperature presentation. The description reproduces not only the field-induced magnetic transition and the temperature-induced transition, but also the magnetic hysteresis and the thermal hysteresis. Also, it gives the critical external field and the critical temperature for the magnetic hysteresis and the thermal hysteresis.