Localized spin-flip excitations in hexagonal HoMnO3

Abstract

Growing demands for ultra-fast switching of spins have turned attention to optically controlled spintronics, which indeed has recently been demonstrated promising. Here we report localized spin-flip excitations revealed by resonance inelastic light scattering on hexagonal holmium manganite thin films with the magnetic manganese ions substituted by the nonmagnetic gallium ions (HoMn1 -xGaxO3). Our analyses on a broad Raman peak support that the corresponding spin excitation is associated with flipping of all three Mn(3+)spins in the elementary trimer of manganese ions and hence maintains the same excitation energy determined by the intrinsic spin-spin interaction between Mn(3+)ions. The nonmagnetic gallium ions only reduce the population of the spin excitations by breaking the spin-frustrated triangular network. Such localized spin-flip excitations show another promise towards optically controlled spin devices.