Polarized Raman scattering in helimagnetic β‐MnO 2

A rutile β‐MnO 2 film was grown on MgO substrate using plasma‐assisted molecular beam epitaxy (PAMBE) monitored by reflection high‐energy electron diffraction (RHEED). Polarized Raman spectra at various temperatures were obtained to investigate the influence of the helimagnetic structure on the vibrational modes of β‐MnO 2 . A red shift of E g modes indicates a gradual formation of spin angles between neighboring Mn 4+ ions. The intensities of the E g and A 1 g modes with y ‐polarized incidence increase remarkably below the Néel temperature. A new view as vibrational mode projection (VMP) indicates the interactions between the magnetic component of incident light and the helimagnetic structure. Copyright © 2008 John Wiley & Sons, Ltd.