We report a comprehensive study of the temperature evolution of in-plane (IP) and out-of-plane (OOP) effective magnetic anisotropies in compensated ferrimagnetic ${\mathrm{Fe}}_{100-x}{\mathrm{Gd}}_x$ alloy films by employing direct current magnetometry and radiofrequency (RF) transverse susceptibility (TS) measurements. We suggest that our ${\mathrm{Fe}}_{100-x}{\mathrm{Gd}}_x$ system is chemically inhomogeneous and phase segregates into Fe- and Gd-enriched regions. Our IP and OOP magnetometry results indicate that the system undergoes a temperature-driven transformation from an IP-spin-configuration-dominated state to an OOP-spin-configuration-dominated state below a certain temperature (spin reorientation temperature). A two-step reversal behavior emerges in the OOP $M$($H$) loop near compensation, which we attribute to the sequential magnetization reversals of Fe- and Gd-enriched domains. Field-induced spin-flop transitions were also observed near the compensation. Our RF TS measurements indicate that the effective magnetic anisotropy for the OOP configuration dominates over that for the IP configuration below a certain spin reorientation temperature. Both IP and OOP anisotropy fields determined from our TS measurement exhibit a minimum around the compensation temperature, which has been explained in the framework of the Stoner-Wohlfarth model.

Understanding of spin-heat coupling mechanisms and magnetothermoelectric phenomena, including the anomalous Nernst effect (ANE), in emergent quaternary Heusler alloys is of practical importance for applications in thermal management and energy harvesting. Here, we demonstrate an intrinsic Berry curvature mediated anomalous Nernst thermopower in CoFeVSb, which orders magnetically at high temperature ($T_C\approx 850\mathrm{K}$) with a large saturation magnetization of $\approx 2.2{\mu }_B/\mathrm{f}.\mathrm{u}.$ at room temperature. We show that the electron-electron elastic and electron-magnon inelastic scattering dominate longitudinal electrical transport at low temperatures ($T\le 50\mathrm{K}$), whereas the electron-phonon and electron-magnon scatterings govern it at higher $T$. The longitudinal thermopower is resulted mainly from the diffusive contribution with a very large longitudinal Seebeck coefficient ($42\mu \mathrm{V}{\mathrm{K}}^{-1}$ at 395 K). The value of the anomalous Nernst coefficient ($S_{\mathrm{ANE}}$) for CoFeVSb at room temperature is $0.039\mu \mathrm{V}{\mathrm{K}}^{-1}$ which is higher than the compressively strained $\mathrm{SrRu}{\mathrm{O}}_3$ film ($0.03\mu \mathrm{V}{\mathrm{K}}^{-1}$) as well as the spin gapless semiconductor CoFeCrGa ($0.018\mu \mathrm{V}{\mathrm{K}}^{-1}$). On lowering $T$, both the ordinary Nernst coefficient and carrier mobility increase but an opposite trend is found for $S_{\mathrm{ANE}}$. Our ab initio simulations reveal the topological semimetallic nature of CoFeVSb with a pair of Weyl points. These Weyl crossings result in a significant contribution to the Berry curvature, leading to an intrinsic anomalous Hall conductivity (${\sigma }_{xy}^{\mathrm{AHE}}$) of $\approx 85$ S/cm, which matches well with experiment (77 S/cm at 2 K). Our experimental findings and ab initio calculations support the dominance of the intrinsic Berry curvature in the observed ANE. The ratio of ${\sigma }_{xy}^{\mathrm{AHE}}$ to the transverse anomalous thermoelectric conductivity (${\alpha }_{xy}^{\mathrm{ANE}}$) shows an increasing trend with $T$ attaining a sizable fraction of $\frac{k_B}{e}\left(\approx 0.35\frac{k_B}{e}\right)$ at room temperature.

Magnetic field dependent electrical resistivity (ρ), thermal conductivity (κ) and thermopower (S) of polycrystalline La_0.9Na_0.1MnO₃ have been reported and the possible mechanisms are discussed.