Effects of magnetic and structural phase transitions on the normal and anomalous Hall effects in Ni-Mn-In-B Heusler alloys

Abstract

Magnetization, electrical resistivity, magnetoresistance, and Hall resistivity of Ni50Mn35In14.25B0.75 and Ni50Mn35In14.5B0.5 Heusler alloys were studied in a temperature range T = 80-400 K in magnetic fields up to 20 kOe. Both alloys exhibit a martensitic transformation from a high-temperature ferromagnetic austenite phase to a low-temperature, low-magnetization martensitic phase. The electrical resistivity nearly doubles as a result of the martensitic transformation, reaching 180 and 100 µΩcm in the martensitic states of Ni50Mn35In14.25B0.75 and Ni50Mn35In14.5B0.5, respectively. The temperature dependence of the electrical resistivity does not corresponded with the Mooij correlation. The magnetoresistance is negative with a narrow negative peak at the martensitic transition. Normal and anomalous Hall effect coefficients were determined by fitting the field dependencies of the Hall resistivity using magnetization data. The coefficients of the normal Hall effect for both compositions were found to decrease with temperature from positive values in the austenite to negative values in the martensite phase.None of the known correlations between the anomalous Hall effect coefficient and resistivity were satisfied. Significant changes in the values of the anomalous Hall coefficients during the martensitic transformation are explained by the difference in spin-up and spin-down state 2 occupations in the martensite and austenite phases. First-principle calculations of the electronic structures confirm this explanation.

Electrical and Magnetic Transport Properties of Co2VGa Half-Metallic Heusler Alloy

“…This result suggests that the direct correlation between the AHE and half-metallicity cannot be found in our studied alloy. At the same time, it is noticeable that the of the studied alloy arrives ~8.3 μΩ·cm/T at 300 K, which is at least dozens of times larger than that reported for the Co 2 FeSi monocrystal [ 33 ] and Co 2 FeAl polycrystal [ 23 ] alloys, as well as greatly exceeding that reported in the Ni-Mn-based metamagnetic Heusler alloy near room temperature [ 34 ]. Such a relatively high exhibited by the studied alloy can be interpreted as the fact that it has a lower .…”

Variation of Electrical Resistivity During Magnetic Field-Induced Martensitic Transformation in Vanadium added NiMnSnB alloys

“…According to Mooij's rule, the resistivity should decrease with increasing temperature when the resistivity of the alloy exceeds 150μΩcm, regardless of the scattering mechanism of the charge carriers. The resistivity of Heusler alloys is can suitable to this rule, while it can be similar to metallic behavior, depending on the composition of the alloy [13][14][15][16]. The resistivity vs temperature curves of Ni49-xVxMn37Sn12B2 (x = 0, 1, 2, and 3) alloys are given in Figure 3.…”

Intrinsic anomalous Hall conductivity and real space Berry curvature induced topological Hall effect in Ni2MnGa magnetic shape memory alloy

“…Anomalous Hall effect (AHE) is one of the intriguing phenomena in condensed matter physics [1][2][3][4], received tremendous attention due to its potentiality as the new generation of conventional electronics in the form of spin-based memory devices for e.g. spintronic devices (magnetic random access memory devices) [1,5], spin orbitronic devices [6], Hall sensor; as well as in the fundamental physics to detect the proposed to understand the AHE in the magnetic materials. In magnetic materials, the scattering of conduction electrons with spin-orbit coupled magnetic impurities leads to the scatteringdependent skew scattering and side jump mechanisms to the AHE [1,12].…”