Electrically driven spin excitation at THz frequencies in bc and ab spiral spin phases of perovskite manganites

Abstract

Here we overview the low-energy (1-10 meV) electrodynamics of spin excitations in a family of ferroelectric perovskite manganites, DyMnO3 and Gd0.7Tb0.3MnO3. By using THz time-domain spectroscopy, we show the compelling evidence that the electric-dipole active spin excitation around 2 meV emerges only along the a-axis, irrespective of the direction of the spiral spin plane (bc or ab). We sum up the general features of the spin excitations, as observed at THz frequencies in ferroelectric perovskite manganites, by taking DyMnO3 and Gd0.7Tb0.3MnO3 as typical examples.