Magnetic-field-tunable charge carrier localization in sintered polycrystalline La0.75Ca0.25Mno3

Abstract

We report broadening of Raman spectrum and decreasing intensity over a range from 400 to 900 cm-1 for sintered polycrystalline La0.75Ca0.25MnO3 in the presence of an external magnetic field. The observation of "structural changes" when the magnetic field is applied can be explained in terms of the canonical orthorhombic distortions, which can be tuned by an applied magnetic field. Based on the interplay between the double exchange and Jahn-Teller electron-phonon coupling, we interpret this phenomenon as spectroscopic evidence of the strong coupling between magnetic field and the lattice leading to an additional tuneable charge carrier localization in the double exchange model.