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Register a new userMagnetic phase diagram and transport properties of FeGe_2
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We have used resistivity measurements to study the magnetic phase diagram of the itinerant antiferromagnet FeGe_2 in the temperature range from 0.3->300 K in magnetic fields up to 16 T. In contrast to theoretical predictions, the incommensurate spin density wave phase is found to be stable at least up to 16 T, with an estimated critical field mu _0H_c of ~ 30 T. We have also studied the low temperature magnetoresistance in the [100], [110], and [001] directions. The transverse magnetoresistance is well described by a power law for magnetic fields above 1 T with no saturation observed at high fields. We discuss our results in terms of the magnetic structure and the calculated electronic bandstructure of FeGe_2. We have also observed, for the first time in this compound, Shubnikov-de Haas oscillations in the transverse magnetoresistance with a frequency of 190 +- 10 T for a magnetic field along [001].
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We describe a method to probe the quantum phase transition between the short-range topological phase and the long-range topological phase in the superconducting Kitaev chain with long-range pairing, both exhibiting subgap modes localized at the edges. The method relies on the effects of the finite mass of the subgap edge modes in the long-range regime (which survives in the thermodynamic limit) on the single-particle scattering coefficients through the chain connected to two normal leads. Specifically, we show that, when the leads are biased at a voltage V with respect to the superconducting chain, the Fano factor is either zero (in the short-range correlated phase) or 2e (in the long-range correlated phase). As a result, we find that the Fano factor works as a directly measurable quantity to probe the quantum phase transition between the two phases. In addition, we note a remarkable critical fractionalization effect in the Fano factor, which is exactly equal to e along the quantum critical line. Finally, we note that a dual implementation of our proposed device makes it suitable as a generator of large-distance entangled two-particle states.
Low-temperature, high-field (H[-110] <= 7.5 T), neutron diffraction experiments on single-crystal Ce0.70Pr0.30B6 are reported. Two successive incommensurate phases are found to exist in zero field. The appearance, for H >= 4.6 T at T = 2 K, of an antiferromagnetic structure, k{AF} = (1/2, 1/2, 1/2), most likely due to an underlying antiferroquadrupolar order, is discussed in connection with recent x-ray diffraction experiments.
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Comprehensive studies of magnetic properties of GdCr3(BO3)4 single crystal have been carried out. The integrals of intrachain and interchain exchange interactions in the chromium subsystem have been determined and the strength of Cr-Gd exchange interaction has been estimated. The values of the exchange field and the effective magnetic anisotropy field of GdCr3(BO3)4 have been estimated. The electric polarization along the a axis in the longitudinal geometry of the experiment has been detected. Correlations between the electric polarization and the magnetization of the studied compound have been found. The spin-reorientation phase transition in the magnetically ordered state has been found. This transition exists for the external magnetic field applied along any crystallographic direction and the transition field depends weakly on the direction of the field. The nature of the spin-reorientation phase transition has been discussed. Magnetic phase diagram has been constructed and spin configurations for the low-field and high-field phases have been proposed.
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