Quantum Stoner-Wohlfarth model of two-dimensional single-domain magnets

The Stoner-Wohlfarth model is a classical model for magnetic hysteresis of single-domain magnets. For two-dimensional (2D) magnets at finite temperatures, the Stoner-Wohlfarth model must be extended to include intrinsic strong spin fluctuations. We predict several fundamentally different hysteresis properties between 2D and 3D magnets. The magnetization switching diagram known as the astroid figure in the conventional Stoner-Wohlfarth model becomes highly temperature dependent and asymmetric with respect to the transverse and longitudinal magnetic fields. Our results provide new insights into the spintronics applications based on 2D magnetic materials.