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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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Journal ArticleDOI
05 Apr 1996-Science
TL;DR: In this paper, a single crystal of perovskite-type manganese oxide with finely controlled ionic radii of the A sites, (Nd,Sm) 1/2 Sr 1/1/2 MnO 3, was modeled as a first-order insulator-to-metal phase transition induced by a magnetic field.
Abstract: Magnetoresistance resulting in a drop in resistivity of more than three orders of magnitude that is strongly coupled to lattice striction has been observed under a relatively low magnetic field (0.4 tesla at 115 kelvin) for a single crystal of perovskite-type manganese oxide with finely controlled ionic radii of the A sites, (Nd,Sm) 1/2 Sr 1/2 MnO 3 . The colossal magnetoresistance phenomena are viewed as a first-order insulator-to-metal phase transition induced by a magnetic field, which accompanies a metamagnetic (antiferromagnetic-to-ferromagnetic) transition and a structural change in the lattice. Clear hystereses and abrupt changes in magnetization, striction, and resistivity were observed in increasing and decreasing magnetic fields at temperatures (113 to 150 kelvin) just above the Curie temperature.

122 citations

Journal ArticleDOI
TL;DR: Magnetoresistance observed in pressed powder compacts of half-metallic ferromagnetic oxides is reviewed in this article, where the main, isotropic negative magnetoresistance, which exceeds 50% in CrO2 at low temperature, is due to alignment of the moments of contiguous Ferromagnetic grains. But the effect is related to interparticle tunelling and shows hysteresis similar to that of the bulk magnetization.
Abstract: Magnetoresistance observed in pressed powder compacts of half-metallic ferromagnetic oxides is reviewed. The main, isotropic negative magnetoresistance, which exceeds 50% in CrO2 at low temperature, is due to alignment of the the ferromagnetic moments of contiguous ferromagnetic grains. The effect is related to interparticle tunelling and shows hysteresis similar to that of the bulk magnetization. Spin-dependent Coulomb blocade observed in the smallest particles. There is also, an anisotropic magnetoresistance of up to 1% and a high-field increase in conductivity of order 1%/T in the powder compacts.

121 citations

Journal ArticleDOI
TL;DR: In this article, the thermal conductivity of manganite perovskite compounds at temperatures 10,350k and fields up to 6T was investigated. But the thermal properties of mangaite pervskite are not related to quenched structural disorder, but rather to unusually large dynamic lattice distortions accompanying charge transport.
Abstract: We present the thermal conductivity ({kappa}) of several manganite perovskite compounds at temperatures 10{endash}350K and fields up to 6T. In the metallic phase, {kappa} behaves as expected for a crystalline solid. In the high-temperature insulating phase, however, d{kappa}/dT{gt}0, the behavior of an amorphous solid. Unlike amorphous solids, d{kappa}/dT{gt}0 here is related not to quenched structural disorder but rather to unusually large dynamic lattice distortions accompanying charge transport. Thus, {open_quotes}colossal magnetoresistance{close_quotes} in the manganite perovskites is characterized as a transition between regimes of different lattice dynamics. {copyright} {ital 1997} {ital The American Physical Society}

121 citations

Journal ArticleDOI
TL;DR: In this paper, the authors employed few-cycle multi-terahertz pulses to probe the evolution of the spin-density-wave (SDW) gap of the pnictide compound BaFe2As2 following excitation with a femtosecond optical pulse.
Abstract: The interplay among charge, spin and lattice degrees of freedom in solids gives rise to intriguing macroscopic quantum phenomena such as colossal magnetoresistance, multiferroicity and high-temperature superconductivity. Strong coupling or competition between various orders in these systems presents the key to manipulate their functional properties by means of external perturbations such as electric and magnetic fields or pressure. Ultrashort and intense optical pulses have emerged as an interesting tool to investigate elementary dynamics and control material properties by melting an existing order. Here, we employ few-cycle multi-terahertz pulses to resonantly probe the evolution of the spin-density-wave (SDW) gap of the pnictide compound BaFe2As2 following excitation with a femtosecond optical pulse. When starting in the low-temperature ground state, optical excitation results in a melting of the SDW order, followed by ultrafast recovery. In contrast, the SDW gap is induced when we excite the normal state above the transition temperature. Very surprisingly, the transient ordering quasi-adiabatically follows a coherent lattice oscillation at a frequency as high as 5.5 THz. Our results attest to a pronounced spin-phonon coupling in pnictides that supports rapid development of a macroscopic order on small vibrational displacement even without breaking the symmetry of the crystal.

120 citations

Journal ArticleDOI
TL;DR: Recent measurements of the magnetoresistance of artificial grain boundaries in thin–film bicrystals suggest that spin–polarized tunnelling and spin scattering at interfaces play a relatively minor role, the dominant low–field contribution to magnetores resistance coming from the mesoscale response of magnetic inhomogeneity induced by the grain boundary.
Abstract: Although theoretical understanding of doped mixedvalence manganites that exhibit colossal magnetoresistance (CMR) is still incomplete, the general observation of a systematic correlation at a given...

119 citations


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Performance
Metrics
No. of papers in the topic in previous years
YearPapers
202330
202252
202139
202038
201937
201837