Ultrasonic evidence for magnetoelastic coupling inLa0.60Y0.07Ca0.33MnO3perovskites

Abstract

The longitudinal and transverse ultrasonic velocities and attenuations of single-phase polycrystalline colossal magnetoresistance compound ${\mathrm{La}}_{0.60}{\mathrm{Y}}_{0.07}{\mathrm{Ca}}_{0.33}{\mathrm{MnO}}_{3}$ have been measured at a frequency of 10 MHz, between 50 and 300 K. At the ferromagnetic and insulator-metal phase-transition temperature ${T}_{c},$ a dramatic increase in sound velocity accompanying an attenuation peak was observed in both the longitudinal and transverse modes. This simultaneous occurrence of magneton, electron, and lattice ordering features implies strong spin-phonon coupling and electron-phonon coupling, known to exist for the octahederally coordinated ${d}^{4}$ ion and originating in the Jahn-Teller effect.