Latest Science Highlights
Polaron Coherence Condensation in Layered Colossal Resistive ManganitesNovel quantum phenomena, such as high-temperature superconductivity (HTSC) and colossal magnetoresistance (CMR), arise in certain materials where the interactions between electrons are very strong, but the mechanism driving their appearance remains a major puzzle. Now, angle-resolved photoemission findings from an international team led by researchers from Stanford University and the ALS provide the first direct spectroscopic evidence that the transition from insulator to metal in CMR manganese oxides (manganites) results from coherent "polaron condensation." The new findings also suggest that coherence-driven transitions are a generic controlling factor for novel quantum phenomena in doped transition-metal oxides. |
Electric-Field Control of Local Ferromagnetism with a Magnetoelectric MultiferroicMagnetoelectric multiferroics—materials that simultaneously show some form of magnetic and ferroelectric order—have excited condensed-matter researchers worldwide with the promise of coupling between magnetic and electric order parameters. A Berkeley–Stanford–Swiss group has now used the multiferroic bismuth–iron–oxygen compound BiFeO3 (BFO) to explore electrical control of magnetism through exchange coupling with a ferromagnet. Their experiments reveal the possibility of controlling ferromagnetism with an electric field at room temperature, a capability that could result in new and novel devices for magnetic data storage, spintronics, and high-frequency magnetic devices. |
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