Temperature dependence of exchange stiffness and energy barrier in compensated ferrimagnets

Ferrimagnetic materials provide unique opportunities for different technological applications such as spintronics through the interplay of ferro- and antiferromagnetic interactions. Particularly interesting is their dynamical behavior around the compensation temperature (${T}_{\text{comp}}$), where the net magnetization vanishes and thus the ferromagneticlike behavior turns to the pure antiferromagnetic one. Due to the significance of this point, it is important to elucidate the temperature dependence of magnetic properties such as the exchange stiffness $A(T)$ and the anisotropy constant $K(T)$ in ferrimagnets. In this study, we use atomistic spin simulations to calculate the temperature dependence of these parameters in ferrimagnetic materials with and without the magnetization compensation point by varying the intersublattice antiferromagnetic exchange parameter. The exchange stiffness $A(T)$ is extracted from the domain wall width. We found that the domain wall width in ferrimagnetic materials increases with temperature more rapidly than in ferromagnetic materials and discuss its scaling with sublattice magnetizations. The temperature dependence of the anisotropy constant, $K(T)$, and the inverse attempt frequency are obtained by mapping Langevin dynamics simulations for switching time of a ferrimagnetic nanoparticle to the Arrhenius-N\'eel law. We found rapid fluctuations of total magnetization near the compensation point which drastically influences the switching probability. Our work deepens the understanding of the behavior of ferrimagnets in technologically relevant regimes (particularly near ${T}_{\text{comp}}$) and lays the groundwork for their more accurate multiscale modeling.