Polarization-coupled magnetization switching in double perovskite oxides

We investigate polarization-coupled magnetization ($P$-coupled-$M$) switching and strain-induced metal-to-insulator transition in ${\mathrm{AA}}^{\ensuremath{'}}{\mathrm{BB}}^{\ensuremath{'}}{\mathrm{O}}_{6}$ double perovskites, using ${\mathrm{Sr}}_{2}{\mathrm{FeMoO}}_{6}$ as an example. First-principles calculations and ab initio molecular dynamics simulations reveal an unconventional octahedral tilt precession (${Q}_{Tp}$) facilitating efficient $P$-coupled-$M$ switching with a lower energy barrier compared to conventional hybrid improper ferroelectric modes. In ${\mathrm{KLaFeMoO}}_{6}$, strain engineering effectively modulates electronic and magnetic properties, demonstrating a strain-induced transition from a ferroelectric half-metallic ferromagnet to an antiferroelectric insulator. In this system, we have observed $P$-coupled-$M$ switching at 450 K. Monte Carlo simulations confirm the thermal stability and N\'eel temperature of the antiferromagnetic phase as 480 K. These results highlight the potential of ${\mathrm{KLaFeMoO}}_{6}$ for high-temperature spintronic applications.