Scaling spin–phonon and spin–spin interactions in magnetoelectric Gd1−xYxMnO3

Abstract

We present a systematic study of the structure and lattice dynamics at room temperature, and the phonon behavior at low temperatures in orthorhombic Gd1−xYxMnO3 manganites, with 0≤x≤0.4. Powder x-ray diffraction and Raman scattering at ambient conditions reveal that the Jahn–Teller distortion is composition-independent, while the Mn–O1–Mn bond angle increases by about 0.5° from x=0 to x=0.4. The spin–phonon coupling was ascertained from the relation between the renormalized wavenumber of the in-plane O2 stretching mode, associated with the spin–spin correlation function. The balance between competitive magnetic interactions is discussed based on the temperature dependence of the phonon frequency renormalization.