Topic
Colossal magnetoresistance
About: Colossal magnetoresistance is a research topic. Over the lifetime, 3658 publications have been published within this topic receiving 130104 citations.
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TL;DR: The large magnetoresistance observed in the manganese-oxide-based perovskites is explained on the basis of a strong electron-phonon and ferromagnetic interactions which provide the mechanism for the existence of dynamic electronic phase segregation in the form of magnetic polarons as mentioned in this paper.
23 citations
TL;DR: In this article, the authors observed large negative magnetoresistance (MR) in Cr•Fe heterogeneous alloy films sputter deposited on heated substrates and the largest MR, 37.3% at 4.2 K and 14 T, appears around the Fe concentration of 20 at.
Abstract: We have observed large negative magnetoresistance (MR) in Cr‐Fe heterogeneous alloy films sputter deposited on heated substrates. The largest MR, 37.3% at 4.2 K and 14 T, appears around the Fe concentration of 20 at. %. While a large substrate temperature dependence of MR is observed when the Fe concentration is lower than 20 at. %, MR does not vary noticeably with changes in the substrate temperature when Fe concentration exceeds 20 at. %.
23 citations
TL;DR: In this article, the authors used tunnelling spectroscopy (TS) to probe the density of states (DOS) of the rare earth manganate, which shows a transition to a charge ordered (CO) antiferromagnetic insulating state from a ferromagnetic metallic state.
Abstract: We have used tunnelling spectroscopy (TS) to probe the density of states (DOS) of the rare earth manganate , which shows a transition to a charge ordered (CO) antiferromagnetic insulating state from a ferromagnetic metallic state. We find that a gap opens up in the DOS around the Fermi level, , as the solid is cooled below the charge ordering temperature . The charge ordering gap was found to be strongly temperature dependent for and for it reaches a limiting value of nearly 0.27 eV. Above the temperature dependence of the DOS at was found to be similar to that of the solids such as which show colossal magnetoresistance but no charge ordering.
23 citations
Journal Article•
TL;DR: In this article, high-resolution x-ray-absorption near-edge structure measurements at the Mn K edge as a function of temperature are reported, with a focus mainly on the pre-edge region.
Abstract: We report high-resolution x-ray-absorption near-edge structure measurements at the Mn K edge as a function of temperature, for ${\\mathrm{La}}_{1\\ensuremath{-}x}{\\mathrm{Ca}}_{x}{\\mathrm{MnO}}_{3}$ samples, with a focus mainly on the pre-edge region. Small peaks labeled ${A}_{1}--{A}_{3}$ are observed which correspond to $1s\\ensuremath{-}3d$ dipole transitions, made weakly allowed via a hybridization of Mn $4p$ states with Mn $3d$ states on neighboring atoms. Adjusting the parameters in a local spin-density approximation calculation to approximately match the experimental ${A}_{1}\\ensuremath{-}{A}_{2}$ splitting yields $U=4$ eV and ${J}_{H}=0.7$ eV. For colossal magnetoresistance samples, ${A}_{1}$ decreases with T while ${A}_{2}$ increases with T below ${T}_{c},$ which shows that the $3d$ bands change significantly as T moves through ${T}_{c}.$ There are also small changes in the shape of the main edge $(1s\\ensuremath{-}4p$ transitions).
23 citations