Search

The resistivity ρ, magnetoresistance Δρxx/ρ0(P), and Hall coefficient RH are measured in a (Cd1 ‒ xZnx)3As2 sample with х = 0.31 under the action of uniform pressure and at various temperatures in the range 80–400 K. These samples are obtained by the modified Bridgman method. The composition of the samples and their homogeneity are controlled by X-ray phase analysis and energy-dispersive X-ray spectroscopy. The results of energy dispersive X-ray spectroscopy show that the distribution of elements in the sample is uniform. It is found that the resistivity increases with increasing temperature, and the change in ρ(T) has a metallic character. The Hall coefficient RH in the field decreases slightly with increasing temperature and retains a negative sign throughout the entire range under study. With increasing pressure, anomalies are observed in the baric dependences of the electrical resistivity ρ(Р), magnetoresistance Δρxx/ρ0(Р), and the Hall coefficient RH(Р). Increasing the uniform pressure leads to suppression of the positive magnetoresistance. In the phase-transition region, the negative magnetoresistance at a pressure of Р (2.4–2.7) GPa in a field of 5 kOe is a maximum value of 1.7. [ABSTRACT FROM AUTHOR]

The results of experimental studies of the resistivity, Hall effect, and magnetoresistance of Cd3As2 + kMnAs composites (k = 20, 30, 44.7 mol %) in a toroid-type high-pressure chamber, which makes it possible to create a hydrostatic pressure up to 9 GPa at room temperature in magnetic fields up to 5 kOe, are presented. With increasing pressure, the electrical resistance of samples with different manganese contents is shown to increase at different rates. In the pressure range 4.2–4.4 GPa, a reversible structural transition is observed. An increase in pressure suppresses the positive component of the magnetoresistance; at pressures of P ≈ 1.0 and P ≈ 2.6 GPa, a region of negative magnetoresistance is observed. With a further increase in pressure, the magnetoresistance increases nonmonotonically up to Р ≈ 4.3 GPa, i.e., the phase transition region. [ABSTRACT FROM AUTHOR]

The results of studying the thermal emf of composites Cd3As2 + n mol % MnAs (n = 10, 20, 30, 44.7) at high pressures up to 50 GPa are presented. In the pressure ranges of P = 28–35 GPa (n = 10, 20), 20–35 GPa (n = 30), and 30–35 GPa (n = 44.7), all the materials studied exhibit specific features in the behavior of the thermal emf S(P) (extrema, inflection points on the curves or hysteresis). At a pressure exceeding 40 GPa, the thermal emf changes weakly or barely changes with an increase and a subsequent decrease in pressure. [ABSTRACT FROM AUTHOR]

In this article, we report research data for the isothermal magnetization of a composite consisting of Cd3As2 Dirac semimetal and MnAs ferromagnet (30 mol %) at pressures up to 5 GPa. A magnetic transformation in MnAs inclusions, the size of which presumably varies from a micro- to nanoscale, has been found to be similar to that in bulk MnAs compound, except for a hysteresis in the range of magnetostructural transformation. Under hydrostatic pressure, a magnetization maximum has been revealed at pressures P ≥ 0.77 GPa, which is indicative of ferromagnetic ordering improvement. The conclusion has been drawn that that the above features are due to the superparamagnetic nature of nanometer-sized MnAs inclusions in the Cd3As2 matrix. [ABSTRACT FROM AUTHOR]

We have studied the effect of hydrostatic pressure on the galvanomagnetic properties of a Cd3As2 + 20 mol % MnAs alloy in a transverse magnetic field of up to 4 kOe. The pressure dependences of the Hall coefficient and resistivity for the alloy provide evidence of reversible phase transitions. The observed negative magnetoresistance of the alloy is shown to be induced by high pressure. [ABSTRACT FROM AUTHOR]