Electromagnetic generation of acoustic waves near second-order magnetic phase transitions of the “order-disorder” and “order-order” type

In this work, we theoretically and experimentally established the common feature of the evolution of the efficiency of the electromagnetic generation of acoustic waves near the temperatures of second-order magnetic phase transitions characteristic of both the “order-disorder” (Curie point in isotropic ferromagnets) and “order-order” (easy-axis-angular-phase and angular-phase-easy-plane) transitions in uniaxial magnets, which consists in the fact that the peak of efficiency corresponds precisely to these temperatures at any values of the magnetic field even if in a magnetic field these temperatures cease to be the points of phase transitions.