About: Charge ordering is a(n) research topic. Over the lifetime, 3575 publication(s) have been published within this topic receiving 81615 citation(s).
21 Apr 2000-Science
TL;DR: An overview is given here on this "orbital physics," which will be a key concept for the science and technology of correlated electrons.
Abstract: An electron in a solid, that is, bound to or nearly localized on the specific atomic site, has three attributes: charge, spin, and orbital. The orbital represents the shape of the electron cloud in solid. In transition-metal oxides with anisotropic-shaped d-orbital electrons, the Coulomb interaction between the electrons (strong electron correlation effect) is of importance for understanding their metal-insulator transitions and properties such as high-temperature superconductivity and colossal magnetoresistance. The orbital degree of freedom occasionally plays an important role in these phenomena, and its correlation and/or order-disorder transition causes a variety of phenomena through strong coupling with charge, spin, and lattice dynamics. An overview is given here on this "orbital physics," which will be a key concept for the science and technology of correlated electrons.
10 Jun 1999-Nature
Abstract: Colossal magnetoresistance1—an unusually large change of resistivity observed in certain materials following application of magnetic field—has been extensively researched in ferromagnetic perovskite manganites. But it remains unclear why the magnetoresistive response increases dramatically when the Curie temperature (T C) is reduced. In these materials, T C varies sensitively with changing chemical pressure; this can be achieved by introducing trivalent rare-earth ions of differing size into the perovskite structure2,3,4, without affecting the valency of the Mn ions. The chemical pressure modifies local structural parameters such as the Mn–O bond distance and Mn–O–Mn bond angle, which directly influence the case of electron hopping between Mn ions (that is, the electronic bandwidth). But these effects cannot satisfactorily explain the dependence of magnetoresistance on T C. Here we demonstrate, using electron microscopy data, that the prototypical (La,Pr,Ca)MnO3 system is electronically phase-separated into a sub-micrometre-scale mixture of insulating regions (with a particular type of charge-ordering) and metallic, ferromagnetic domains. We find that the colossal magnetoresistive effect in low-T C systems can be explained by percolative transport through the ferromagnetic domains; this depends sensitively on the relative spin orientation of adjacent ferromagnetic domains which can be controlled by applied magnetic fields.
01 May 1998-
Abstract: An aspect of metal oxides, colossal magnetoresistance exhibited by certain manganese oxides, in particular rare-earth manganates of perovskite structure, has received much attention in recent years. Some of these oxides show 100 per cent magnetoresistance, and have potential for technological applications. This text begins with a review of the topics of colossal magnetoresistance, charge ordering and related phenomena exhibited by oxides, and presents contributions covering the present status of the subject.
01 Oct 1999-Journal of Magnetism and Magnetic Materials
Abstract: Magnetoelectronic features of the perovskite-type manganites are overviewed in the light of the mechanism of the colossal magnetoresistance (CMR). The essential ingredient of the CMR physics is not only the double-exchange interaction but also other competing interactions, such as ferromagnetic/antiferromagnetic superexchange interactions and charge/orbital ordering instabilities as well as their strong coupling with the lattice deformation. In particular, the orbital degree of freedom of the conduction electrons in the near-degenerate 3d eg state plays an essential role in producing the unconventional metal–insulator phenomena in the manganites via strong coupling with spin, charge, and lattice degrees of freedom. Insulating or poorly conducting states arise from the long or short-range correlations of charge and orbital, but can be mostly melted or turned into the orbital-disordered conducting state by application of a magnetic field, producing the CMR or the insulator–metal transition.
14 Jan 2011-Science
TL;DR: Mid-infrared femtosecond pulses are used to enable coherent transport between the copper oxide planes of a cuprate superconductor, and an upper limit for the time scale needed to form the superconducting phase is estimated to be 1 to 2 picoseconds, which places stringent new constraints on the understanding of stripe order and its relation to superconductivity.
Abstract: One of the most intriguing features of some high-temperature cuprate superconductors is the interplay between one-dimensional "striped" spin order and charge order, and superconductivity. We used mid-infrared femtosecond pulses to transform one such stripe-ordered compound, nonsuperconducting La(1.675)Eu(0.2)Sr(0.125)CuO(4), into a transient three-dimensional superconductor. The emergence of coherent interlayer transport was evidenced by the prompt appearance of a Josephson plasma resonance in the c-axis optical properties. An upper limit for the time scale needed to form the superconducting phase is estimated to be 1 to 2 picoseconds, which is significantly faster than expected. This places stringent new constraints on our understanding of stripe order and its relation to superconductivity.