Temperature dependence of the exchange anisotropy of a GdFeCo ferrimagnetic film coupled to the IrMn antiferromagnet

The uniaxial anisotropy and kinetics of the transformation of the domain structure in a ferrimagnetic GdFeCo film exchange-coupled to the IrMn antiferromagnet have been studied in a wide temperature range. Ta/Pt/GdFeCo/IrMn/Pt multilayer structures with perpendicular magnetic anisotropy demonstrate the compensation of the sublattice magnetization at K and K. Nonmonotonic temperature dependences of the exchange bias field $H_{\mathrm{EX}}$ and coercivity $H_C$ are revealed. It is established that the slope of the dependence and the quantity $H_{\mathrm{EX}}$ change sign at $T_1$. An orientational phase transition is detected at a temperature of $T_{\mathrm{CR}}=35$ K, below which uniaxial anisotropy, as well as the mechanism of coercive force formation, changes.