Large magnetic Bragg peak enhancement by ultrasound injection on FeTiO₃

FeTiO₃ is an ilmenite antiferromagnetic insulator containing Fe²⁺, with two-dimensional ferromagnetic honeycomb layers antiferromagnetically stacked along the c-axis. The magnetic Bragg peak intensity is found to be enhanced under the application of ultrasound up to 300% in FeTiO₃ crystals at low temperatures. The pronounced enhancement is attributed to strong spin-lattice coupling of Fe²⁺ in FeTiO₃. This effect disappears above 35 K, suggesting that the energy splitting of Fe²⁺ levels induced by spin-orbit coupling is about 35 K. This finding suggests a promising pathway toward high efficiency acoustic spin pumping.