Hall Coefficient Of Samples Research Articles

A ferromagnetic topological half-metal candidate: Carbon-doped Bi2Se3

The high quality CxBi2Se3-x single crystals have been prepared by melt-grown reaction. The transport characteristicsmeasurement showed that the doping leads to the presence of ferromagnetism and the high external magnetic field could induce the metal-insulation transition. The metal-insulation transition temperature (Tm) is 169 K and 253 K for 6 T and 9 T, respectively. Analyze the curves of ρxy-B, we used the two-band model to fit MR and Hall coefficient of samples. The results indicated that electron-hole compensation may not be the only reason for the existence of unsaturated magnetoresistance in the material. To further, first principles are used to calculate the band structure of CxBi2Se3-x single crystals, and the feature of the topological half-metals has been suggested. According to the above results, we infer that CxBi2Se3-x single crystals may be candidate materials for topological half-metals.

Hall effect in crystalline Ni-Fe-Cr alloys showing resistivity minima

The temperature dependence of Hall resistivity $({\ensuremath{\rho}}_{H})$ is presented for magnetic inductions up to 1.3 T and temperatures down to 1.4 K. The samples are ferromagnetic Ni-rich $\ensuremath{\gamma}\ensuremath{-}{\mathrm{Ni}}_{75}{\mathrm{Fe}}_{13}{\mathrm{Cr}}_{12}$ (sample 1), ${\mathrm{Ni}}_{70}{\mathrm{Fe}}_{12}{\mathrm{Cr}}_{18}$ (sample 2), and ${\mathrm{Ni}}_{73.5}{\mathrm{Fe}}_{8}{\mathrm{Cr}}_{18.5}$ (sample 3) alloys. The values of the ordinary ${(R}_{0})$ and the extraordinary ${(R}_{s})$ Hall coefficients are found to be positive in samples 2 and 3 whereas they are negative in sample 1. Electrical-resistivity $[\ensuremath{\rho}(T)]$ studies in these alloys have shown resistivity minima (at ${T}_{\mathrm{min}}$) that are described by electron-electron interaction effects. ${R}_{0}$ is found to be nearly temperature independent in all the alloys. On the other hand, ${R}_{s}(T)$ has shown minima, very similar to those of $\ensuremath{\rho}(T)$ around ${T}_{\mathrm{min}}.$ The temperature dependence of the positive extraordinary Hall coefficient in samples 1 and 3 is consistent with the minima observed in $\ensuremath{\rho}(T),$ whereas the negative extraordinary Hall coefficient in sample 1 behaves exactly opposite to what is expected theoretically, i.e., instead of getting more negative, the coefficient becomes more positive on both sides of ${T}_{\mathrm{min}}.$ This is found to be rather puzzling and cannot be explained in terms of the existing theories. However, the positive ${R}_{s}(T)$ is interpreted indirectly (through their electrical resistivity) by electron-electron interaction effects.

The influence of boron content on the Hall effect and structure of annealed Fe73.5Cu1Nb3Si22.5−xBx (5≤x≤13) alloys

Abstract The influence of boron content and annealing on the Hall effect and structure of amorphous Fe 73.5 Cu 1 Nb 3 Si 22.5− x B x (5≤ x ≤13) ribbons were studied. The annealing at 550°C caused a significant change of structure and Hall coefficient of samples vs. boron content. DSC confirmed the influence of boron content on crystallization temperature of all samples.

Electrical Properties of Heavily Doped Silicon

Measurements have been made of the temperature dependences of the electrical resistivity and Hall coefficient in samples of n- and p-type silicon having impurity concentrations in the 1018 to 1020 cm−3 range. The resistivity data extend from 4° to 900°K, and the Hall data from 4° to 300°K. The results exhibit two noteworthy features: viz., (1) a hump or maximum in the resistivity vs temperature curves at or slightly below the degeneracy temperature in each sample, which is most pronounced in the least heavily doped samples and gradually fades out as the impurity concentration increases, and (2) an extension of the positive dependence of resistivity on temperature below the hump or degeneracy temperature to surprisingly low temperatures in each sample.