Showing papers on "Colossal magnetoresistance published in 1986"
TL;DR: In this article, the magnetoresistance of a series of metallic glasses, including Mg80Cu20, Cu50Lu50, Pd80Si20, Y 80Si20 and Cu57Zr43, was measured at low temperature.
Abstract: The authors present magnetoresistance measurements at low temperature on a series of metallic glasses: Mg80Cu20, Cu50Lu50, Pd80Si20, Cu50Y50, Y80Si20, Cu57Zr43, CuYGd and CuLuGd. The magnetoresistance clearly exhibits three-dimensional localisation effects with a strong influence of the spin-orbit scattering: the magnetoresistance is negative for weak spin-orbit scattering (Mg80Cu20) and positive for strong spin-orbit scattering (Cu50Lu50, Pd80Si20), and changes from positive at low field to negative at high field for intermediate spin-orbit scattering (Cu50Y50, Cu57Zr43). The magnetoresistance curves can be accounted for by only localisation terms for most alloys and interaction effects are significant only for Y80Si20. An additional contribution from superconducting fluctuations is observed for the superconducting alloy Cu57Zr43. The analysis of the magnetoresistance yields the spin-orbit and inelastic scattering rates. The inelastic scattering rate of the alloys varies as T2 at high enough temperature and departs from T2 below about 5K. The measurements in a dilution refrigerator on Cu50Y50 and Y80Si20 have shown a variation as T1/2 below 1K. They discuss the possible origin of such a variation. They finally present measurements on Cu50Y50 and Y80Si20 doped with Gd. Surprisingly the addition of magnetic Gd impurities does not depress strongly the localisation effects, as would be expected from the existing theories.
37 citations
TL;DR: Insulating thin films of indium oxide exhibit negative, anisotropic magnetoresistance and the systematics of these results imply that the Magnetoresistance mechanism may give different weight to the distribution of the localization lengths than that given by the hopping conductivity.
Abstract: Insulating thin films of indium oxide exhibit negative, anisotropic magnetoresistance. The systematics of these results imply that the magnetoresistance mechanism may give different weight to the distribution of the localization lengths than that given by the hopping conductivity.
18 citations
TL;DR: In this article, the magnetoresistance due to variable-range hopping conduction is calculated by the critical path method in the Anderson-localised regime of semiconductors taking into account the electron-electron interaction.
Abstract: The magnetoresistance due to the variable-range hopping conduction is calculated by the critical path method in the Anderson-localised regime of semiconductors taking into account the electron-electron interaction. In the presence of the intra-state interaction, a magnetic field suppresses two types of the hopping process. This results in the positive contribution to the magnetoresistance. The degree of localisation is a function of energy and this feature gives rise to the negative contribution. The total magnetoresistance is positive in low magnetic fields and is negative at high magnetic fields. The inter-state interaction suppresses the positive contribution. The results are compared with those of experiments on 1T-TaS2 and 1T-TaS2-xSe.
10 citations
TL;DR: In this paper, the theoretical basis of the negative magnetoresistance in pre-graphitic carbons is clarified by using a new mechanism due to the field dependence of impurity scattering, where the crystalline order is controlled by the annealing temperature.
5 citations
TL;DR: In this paper, the well known two carrier transverse magnetoresistance in semiconductors is analyzed in order to show that a high magnetoreduction coefficient can be reached for an impurity concentration which closely depends on the electron-hole mobility ratio and the magnetic field intensity.
Abstract: The well known two carrier transverse magnetoresistance in semiconductors is analysed in order to show that a high magnetoresistance coefficient can be reached for an impurity concentration which closely depends on the electron-hole mobility ratio and the magnetic field intensity. The condition for a strong magnetoresistance is shown to be quite different from that leading to a null Hall field. Experiments in InSb crystals fully confirm the analysis and outline the possibility to use this effect for magnetic or temperature sensors.
3 citations
TL;DR: In this paper, the influence of the superconducting phase transition in the solder materials Rose metal (Bi•52.5%, Pb•32%, Sn•15.5%), CdIn alloy (Cd•50, In−50%), and indium on magnetoresistance measurements of (cd1−xMnx)3As2 was examined.
Abstract: We have examined the influence of the superconducting phase transition in the solder materials Rose‐metal (Bi‐52.5%, Pb‐32%, Sn‐15.5%), CdIn alloy (Cd‐50%, In‐50%), and indium on magnetoresistance measurements of (Cd1−xMnx)3As2 . The superconducting phase transition of these solders takes place within the temperature and magnetic field ranges where quantum oscillations of magnetoresistance usually are observed. The appearance of the generated anomalous signals may lead to misinterpretation, in terms of anomalous oscillations of the magnetoresistance or quantization of the surface impedance. We have found a correlation between the magnitude of the anomalous signals and the resistivity ratio of solder and sample material.
2 citations
TL;DR: In this paper, the authors proposed a model to explain electrical conductivity anomalies in magnetic chalcogenide spinels near the Curie point, based on strong electronelectron correlations between d-electrons in the narrow, orbitally degenerate conduction band.
Abstract: We propose a model to explain electrical conductivity anomalies in magnetic chalcogenide spinels near the Curie point. The model is based on strong electronelectron correlations between d-electrons in the narrow, orbitally degenerate conduction band. We demonstrate that in this system spin inhomogeneities produce scattering and lead to strong negative magnetoresistance. Experimental data on the electrical conductivity of the CdCr2Se4 compound in a magnetic field is compared to numerical computation. We explain the absence of magnetoresistance anomalies in p-type samples.
1 citations
TL;DR: In this article, the magnetoresistance of p-type semiconductors was investigated on a two-band model assuming strong spin-orbit coupling, and the value of the magnetoreduction was the same as that of single-band models, contrary to the result of Altshuler et al.
Abstract: The magnetoresistance of p-type semiconductors is investigated on a two-band model assuming strong spin-orbit coupling. The value of the magnetoresistance is the same as that of single-band model, contrary to the result of Altshuler et al. , who predicted the reduction of the magnitude by a factor 2.