Low Energy Excitations in La1.2Sr1.8Mn2O7 investigated by ellipsometry
journal contributionposted on 2020-09-21, 02:42 authored by Ocean MercierOcean Mercier, Robert BuckleyRobert Buckley, Harry TrodahlHarry Trodahl, C Bernhard, B Balakrishnan
The low-energy excitations of the bilayered manganite La1.2 Sr1.8 Mn2 O7 have been explored by spectral ellipsometry from two faces of a single crystal over the range from 0.006 to 0.6 eV. This compound is a paramagnetic insulator at ambient temperature, with a transition to a ferromagnetic metal below a Curie temperature (Tc) of 125 K. Both the ab -plane and c -axis temperature-dependent conductivities have been determined. Essentially no temperature-dependent behavior is observed above Tc although below Tc both the phonon and electronic contributions are strongly temperature sensitive. The highest-frequency phonons, especially those involving Mn-O bond stretching, split and show frequency changes consistent with structural results in the literature, and furthermore there is clear evidence of an increase in electron-phonon coupling at and below Tc. We interpret the temperature-dependent electronic spectral contribution in the light of recent calculations that indicate that a mixed phase exists in the doped manganites below Tc, with coexisting regions of an itinerant large-polaron phase and a localized small-polaron phase. © 2005 The American Physical Society.
Preferred citationMercier, O., Buckley, R., Trodahl, H., Bernhard, C. & Balakrishnan, B. (2005). Low Energy Excitations in La1.2Sr1.8Mn2O7 investigated by ellipsometry. Physical Review B, 72(21), 214437-1:5-. https://doi.org/10.1103/PhysRevB.72.214437
Journal titlePhysical Review B
PublisherAmerican Physical Society (APS)
Online publication date2005-12-29
Science & TechnologyTechnologyPhysical SciencesMaterials Science, MultidisciplinaryPhysics, AppliedPhysics, Condensed MatterMaterials SciencePhysicsTO-POLARON CROSSOVERCOLOSSAL-MAGNETORESISTANCEDOUBLE-EXCHANGEOPTICAL CONDUCTIVITYELECTRONIC-STRUCTUREDOPED MANGANITESLIQUIDREFLECTIVITYLA1-XSRXMNO3RESISTIVITYFluids & PlasmasChemical SciencesEngineering