Tip‐enhanced Raman spectroscopy (TERS) on double perovskite La2CoMnO6 thin films: field enhancement and depolarization effects

• DOI: 10.1002/jrs.4986
• Publication Date: 2016-07-21T12:32:59Z
• Authors: Christoph Meyer; Sebastian Hühn; Markus Jungbauer; Sebastian Merten; Bernd Damaschke; Konrad Samwer; Vasily Moshnyaga
• Keywords: Monoclinic crystal system; Depolarization ratio

Polarization‐dependent tip‐enhanced Raman spectroscopy (TERS) was carried out on double perovskite La 2 CoMnO 6 (LCMO) thin films to determine the contributions of enhancement by excitation surface plasmon polariton and tip‐induced polarization effects. Due B‐site ordering resulting monoclinic P12 1 / n1 structure, spectra exhibit a strong A g mode around 644 cm −1 originated from (Co Mn)O stretching vibrations. The TERS contrast C , defined as ratio total‐field (the sum near field far field) far‐field intensity, up ~ 60–110 for cross‐polarized configuration (incident light perpendicular detected one), reveals possible breakdown polarization‐dependent selection rules scattering due near‐field depolarization component. We disentangled significant all observed modes in parallel with ~2–5 general amplification, strongly affected also film thickness. With highly dielectric behavior, LCMO therefore provides an excellent test system study phenomena oxide surfaces. Copyright © 2016 John Wiley & Sons, Ltd.