Journal ArticleDOI
Giant negative magnetoresistance in perovskitelike La2/3Ba1/3MnOx ferromagnetic films.
R. von Helmolt,R. von Helmolt,Joachim Dr. Wecker,Joachim Dr. Wecker,B. Holzapfel,B. Holzapfel,L. Schultz,L. Schultz,Konrad Samwer,Konrad Samwer +9 more
TLDR
The samples show a drop in the resistivity at the magnetic transition, and the existence of magnetic polarons seems to dominate the electric transport in this region.Abstract:
At room temperature a large magnetoresistance, \ensuremath{\Delta}R/R(H=0), of 60% has been observed in thin magnetic films of perovskitelike La-Ba-Mn-O. The films were grown epitaxially on ${\mathrm{SrTiO}}_{3}$ substrates by off-axis laser deposition. In the as-deposited state, the Curie temperature and the saturation magnetization were considerably lower compared to bulk samples, but were increased by a subsequent heat treatment. The samples show a drop in the resistivity at the magnetic transition, and the existence of magnetic polarons seems to dominate the electric transport in this region.read more
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Journal ArticleDOI
Dynamical mean-field theory of strongly correlated fermion systems and the limit of infinite dimensions
TL;DR: The dynamical mean field theory of strongly correlated electron systems is based on a mapping of lattice models onto quantum impurity models subject to a self-consistency condition.
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Thousandfold Change in Resistivity in Magnetoresistive La-Ca-Mn-O Films
TL;DR: A negative isotropic magnetoresistance effect has been observed in thin oxide films of perovskite-like La0.67Ca0.33MnOx, which could be useful for various magnetic and electric device applications if the observed effects of material processing are optimized.
Journal ArticleDOI
Colossal Magnetoresistant Materials: The Key Role of Phase Separation
TL;DR: In this paper, a large variety of experiments reviewed in detail here contain results compatible with the theoretical predictions, including phase diagrams of manganite models, the stabilization of the charge/orbital/spin ordered half-doped correlated electronics (CE)-states, the importance of the naively small Heisenberg coupling among localized spins, the setup of accurate mean-field approximations, and the existence of a new temperature scale T∗ where clusters start forming above the Curie temperature, the presence of stripes in the system, and many others.
Journal ArticleDOI
REVIEW ARTICLE: Colossal magnetoresistance
TL;DR: In this paper, the authors review recent experimental work falling under the broad classification of colossal magnetoresistance (CMR), which is magnetoreduction associated with a ferromagnetic-toparamagnetic phase transition.
Journal ArticleDOI
Critical features of colossal magnetoresistive manganites
TL;DR: In this paper, the phase separation phenomenon on various time-scales (from static to dynamic) and the enhanced phase fluctuation with anomalous reduction in the transition temperatures of the competing phases (and hence in the bicritical-point temperature).