Generatsiya prodol'nogo ul'trazvuka impul'sami sdvigovoy deformatsii v rezhime spin-fononnogo ekha

Abstract

The possibility of generation of longitudinal ultrasonic pulses of gigahertz frequencies in the spin–phonon echo regime by acting on a magnetized isotropic paramagnet with nanosecond shear strain pulses is predicted. The frequency of generated longitudinal ultrasonic echo signals is twice as high as the frequency of pulses entered into the medium. This effect can be realized when the velocity of longitudinal ultrasound exceeds the velocity of shear strain waves by less than two times. This resonant mechanism of the pulsed regime of second harmonic generation, which is accompanied by a nonlinear transformation of transverse into longitudinal ultrasound, has no optical analog.