Laser-enhanced magnetism in SmFeO₃

The cross-talk between two magnetic ions, Sm³⁺ and Fe²⁺, in samarium ferrite (SmFeO$_3$) leads to a strong interaction of spins and phonons at low temperatures, while the magnetic interactions are weak. In this work, we simulate the dissipative spin dynamics in SmFeO₃ that are coupled to laser-driven infrared-active phonons via linear and quadratic modulation of the exchange energy to coherently enhance spin interactions, referred to as magnetophononics. When linear coupling dominates, we discover a dynamical first-order phase transition in the nonequilibrium steady state which can inhibit strong enhancement of magnetic interactions. By contrast, when quadratic spin-phonon coupling dominates, no phase transition exists at experimentally relevant parameters. By utilizing a chirp protocol, we see that the phase transition can be engineered, enabling stronger magnetic interactions in the steady state, a key goal of magnetophononics. We also discuss the route for experimental observation of our results, as well as the potential application of our theory for functional materials and spintronics.