Skew scattering dominated anomalous Nernst effect in La1-xNaxMnO3

Abstract

We report the anomalous Nernst effect (ANE), i.e. creation of electrical voltage transverse to the direction of applied temperature gradient and magnetic field in bulk samples of La1-xNaxMnO3 (x = 0.02, 0.05, 0.1 and 0.3) whose ferromagnetic Cure temperature(TC) varies from 251 K for x = 0.02 to 310 K for x = 0.3. We measured both the magnetic field and temperature dependences of ANE. While ANE is negligible much above TC, it increases rapidly at TC and exhibits a peak just below it. The field dependence of ANE closely follows magnetization. The maximum value of ANE at TC increases from x = 0.02 to 0.1, but decreases significantly for x = 0.3. Besides ANE, we also measured dc resistivity and longitudinal Seebeck coefficient as a function of temperature and used these data to analyze our results. Our data analysis indicates that skew scattering is the main source of the ANE in these oxides.

Anomalous Nernst Effect and Giant Magnetostriction in Microwave-Synthesized La0.5Sr0.5CoO3

“…Starting from the low-temperature side, S xy (ANE) increases as the temperature increases and reaches a maximum value around 180 K ( S xy (ANE) ∼ 0.21 μV/K for 50 kOe) and decreases rapidly as T C is approached. The maximum value of S xy (ANE) ∼ 0.21 μV/K is comparable to the value observed in single crystal (∼0.26 μV/K) and polycrystalline (∼0.19 μV/K) samples of lower Sr content (La 0.7 Sr 0.3 CoO 3 ) and larger than the maximum value observed in other perovskites of La 1– x Na x MnO 3 (S xy ∼ 5 nV/K) …”

Large Thermo-Spin Effects in Heusler Alloy-Based Spin Gapless Semiconductor Thin Films

“…The ANE refers to the generation of a transverse thermoelectric voltage in a magnetic conductor/semiconductor by the application of a thermal gradient and an external magnetic field . The ANE has been observed in a large range of magnetic materials, from half-metallic ferromagnets such as hole-doped manganites, cobaltites, and spin gapless semiconductors to ferrimagnets such as iron oxide, as well as unconventional magnetic systems with topologically nontrivial phases such as topological full Heusler ferromagnets, ferromagnetic Weyl semimetals, , etc. In a topological magnetic material, charge carriers moving through a periodic potential with strong spin–orbit coupling (SOC) acquire an additional anomalous velocity perpendicular to their original trajectory due to the nonzero Berry curvature at the Fermi level .…”

“…This anomalous velocity causes a real space spin selective deflection of the charge carriers and leads to a potentially large ANE response in these topological magnetic materials compared to conventional magnets . In addition to the aforementioned intrinsic origin, ANE can also originate from extrinsic effects, for example, asymmetric skew scattering of charge carriers as observed in Heusler ferromagnets, hole-doped manganites, cobaltites, spin gapless semiconductors, iron oxide, etc.…”

Signatures of the Magnetic Entropy in the Thermopower Signals in Nanoribbons of the Magnetic Weyl Semimetal Co3Sn2S2

“…Its validity has been investigated systematically in ferromagnets, diluted magnetic semiconductors, and topological materials. − In particular, Pu and co-workers have shown that, under the assumption of a simple power law dependence between ρ xx and ρ yx , the Mott relation leads to two equations for the temperature dependency of S yx and α yx : where λ′/λ and n are temperature-independent parameters resulting from the power law ansatz. One can expect to describe both measurements with the same set of parameters, as successfully done for different materials. ,, The shaded regions in Figure a,b represent the corresponding curves calculated from eqs and , respectively, with λ′/λ = −4.2 × 10 –19 and n = 2.4. Figure c,d displays the difference between the measurements and the calculated curves.…”

“…One can expect to describe both measurements with the same set of parameters, as successfully done for different materials. 39,45,46 The shaded regions in Figure 4a,b represent the corresponding curves calculated from eqs 4 and 5, respectively, with λ′/λ = −4.2 × 10 −19 and n = 2.4. Figure 4c,d displays the difference between the measurements and the calculated curves.…”