1999/12/27 by J. H. Jung, Jong Hoon Jung, H. J. Lee +7 · 2 citations
Materials Science · Physics and Astronomy · #Advanced Condensed Matter Physics #Magnetic and transport properties of perovskites and related materials #Solid-state spectroscopy and crystallography #cond-mat.str-el
paper · pdf · doi:10.1103/physrevb.62.481
submitted to Phys. Rev. B
arxiv created 1999/12/27 · openalex publication_date 2000/07/01 · arxiv updated 2009/11/30 · openalex created_date 2016/06/24 · openalex updated_date 2026/07/28
We investigated the temperature (T=15\ensuremath∼290K) and the magnetic-field-dependent (H=0\ensuremath∼17T) optical conductivity spectra of a charge-orbital-ordered manganite Nd1/2Sr1/2MnO3. With variation of T and H, large spectral weight changes were observed up to 4.0 eV. These spectral weight changes could be explained using the polaron picture. Interestingly, our results suggested that some local ordered state might remain above the charge ordering temperature, and that the charge/orbital melted state at a high magnetic field (i.e., at H=17T and T=4.2K) should be a three-dimensional ferromagnetic metal. We also investigated the first order phase transition from the charge-orbital- ordered state to ferromagnetic metallic state using the T- and H-dependent dielectric constants \ensuremathε. Through the analysis of \ensuremathε using an effective medium approximation, we found that the melting of charge-orbital-ordered states should occur through the percolation of ferromagnetic metal domains.