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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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TL;DR: In this article, an electronic Raman scattering study of manganese perovskites was performed as a function of temperature, magnetic field, symmetry, and doping, and it was shown that strongly field-dependent scattering rate in the 1g channel appears to reflect the highly fielddependent mobility along the Mn-O bond direction expected in the double exchange mechanism.
Abstract: We report an electronic Raman scattering study of the colossal magnetoresistance (CMR) manganese perovskites as a function of temperature, magnetic field, symmetry, and doping. The low-frequency electronic Raman spectrum in the paramagnetic-insulating phase of these materials is characterized by a diffusive Raman-scattering response, while a nearly flat continuum response is observed in the ferromagnetic-metallic state. We found that the ${B}_{1g}$-symmetry electronic scattering intensity is significantly reduced with applied magnetic field near ${T}_{C},$ in a manner reminiscent of the dc magnetoresistivity. The strongly field-dependent scattering rate in the ${B}_{1g}$ channel appears to reflect the highly field-dependent mobility along the Mn-O bond direction expected in the double exchange mechanism. In addition, we observe a persistent field dependence in the ${B}_{1g}$ electronic scattering response for $T\ensuremath{\ll}{T}_{C},$ suggesting that the ferromagnetic phase is inhomogeneous, perhaps consisting of both metallic and insulating components.

25 citations

Journal ArticleDOI
TL;DR: In this paper, strong anisotropic magnetoresistance (AMR) was observed in La0.67Ca0.33MnO3 films grown coherently on the orthorhombic NdGaO3(001) substrates.
Abstract: Strong anisotropic magnetoresistance (AMR) was observed in La0.67Ca0.33MnO3 films grown coherently on the orthorhombic NdGaO3(001) substrates. With an increased orthorhombic lattice distortion due to the pseudomorphic strain, the films show not only a ferromagnetic-metal (FM) transition at TC of ∼265 K, but also the phase coexistence of FM and antiferromagnetic-insulator below ∼250 K. The phase competitions are very sensitive to the magnetic field, and more strikingly, to its orientations with respect to the crystal axes resulting in a large AMR in a broad temperature range, in addition to the conventional one peaked near TC. The films also show uniaxial magnetic anisotropy with the easy axis along the elongated b axis, suggesting that it is the strain induced spin-orbit-lattice coupling and the resultant phase competitions that control the AMR in epitaxial manganite films.

25 citations

Journal ArticleDOI
TL;DR: In this paper, the influence of oxygen content on the magnetization and electrical resistivity of hole-doped perovskite manganites was investigated and it was shown that the La0.5Ca 0.5A0.3−γ compound undergoes a sequence of transitions from an antiferromagnetic (γ = 0) to a spin-glass (γ=0.17) state and then to an inhomogeneous ferromagnetic charge-disordered state.
Abstract: The influence of oxygen content on the magnetization and electrical resistivity of Ln0.5A0.5MnO3 (Ln=La, Pr, Nd; A=Ca, Ba) manganites with the perovskite structure is investigated. It is shown that the La0.5Ca0.5MnO3−γ compound undergoes a sequence of transitions from an antiferromagnetic (γ=0) to a spin-glass (γ=0.17) state and then to an inhomogeneous ferromagnetic (γ=0.3) state. A transition from an antiferromagnetic charge-ordered state to a ferromagnetic charge-disordered state in Nd0.5Ca0.5MnO3−γ is observed as the oxygen content is reduced to where γ=0.07. The Nd0.5Ba0.5MnO3−γ compound shows an increase of the Curie point from 110 K(γ=0) to 310 K(γ=0.3). In addition, a large magnetoresistance is revealed which develops below their Curie temperature despite the absence of Mn3+−Mn4+ pairs. A Zener double-exchange interaction is usually used in literature to explain the magnetic and electrical properties of hole-doped perovskite manganites. The data obtained support the mechanism of superexchange inte...

25 citations

Journal ArticleDOI
TL;DR: In this paper, the synthesis, electrical transport, and magnetic properties of Pr-doped LaMnO3 ceramic material were reported. But they did not report on the synthesis and electrical transport properties of the material.
Abstract: We report a study on the synthesis, electrical transport, and magnetic properties of Pr-doped LaMnO3 ceramic material. We have found that La1−xPrxMnO3+δ (x=0.3) synthesized using solid-state reaction shows semiconductor behavior, and no colossal magnetoresistance (CMR) effect; while it shows CMR behavior when it is annealed in a flowing argon at certain temperature (about 873 K), which suggests that La0.7Pr0.3MnO3+δ has been transferred to La0.7Pr0.3MnO3. The x-ray photoemission spectroscopy reveals that Pr ions are in a mixed-valence state of Pr4+ and Pr3+ in this compound. Therefore, La1−xPrxMnO3 (x=0.3) could be an electron-doped CMR manganite.

25 citations

Journal ArticleDOI
TL;DR: In this paper, a simplified model for the colossal magnetoresistance in doped manganites was presented by exactly solving a double-exchange model with Ising-like local spins and quenched binary disorder within dynamical mean field theory.
Abstract: We present a simplified model for the colossal magnetoresistance in doped manganites by exactly solving a double-exchange model (with Ising-like local spins) and quenched binary disorder within dynamical mean field theory. We examine the magnetic properties and the electrical and thermal transport. Our solution illustrates three different physical regimes: (i) a weak-disorder regime, where the system acts like a renormalized double-exchange system (which is insufficient to describe the behavior in the manganites); (ii) a strong-disorder regime, where the system is described by strong-coupling physics about an insulating phase (which is the most favorable for large magnetoresistance); and (iii) a transition region of moderate disorder, where both double-exchange and strong-coupling effects are important. We use the thermopower as a stringent test for the applicability of this model to the manganites and find that the model is unable to properly account for the sign change of the thermopower seen in experiment.

25 citations


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