Intrinsic Spin-Dependent Thermal Transport

Abstract

Most studies of spin caloritronic effects to date, including spin-Seebeck effect, utilize thin films on substrates. We use patterned ferromagnetic thin film to demonstrate the profound effect of a substrate on the spin-dependent thermal transport. With different sample patterns and on varying the direction of temperature gradient, both longitudinal and transverse thermal voltages exhibit asymmetric instead of symmetric spin dependence. This unexpected behavior is due to an out-of-plane temperature gradient imposed by the thermal conduction through the substrate and the mixture of anomalous Nernst effects. Only with substrate-free samples have we determined the intrinsic spin-dependent thermal transport with characteristics and field sensitivity similar to those of the anisotropic magnetoresistance effect.

Thermally driven spin and charge currents in thin NiFe2O4/Pt films

“…Here, E ANE is the electromotive force, α a coefficient describing the magnitude of the ANE, ∇T the temperature gradient and m the unit vector of magnetization 13 . In the LSSE configuration, Eq.…”

Large anomalous Nernst effect at room temperature in a chiral antiferromagnet

“…This trend has also triggered renewed interest in the anomalous Nernst effect (ANE) in ferromagnetic metals [3][4][5][6][7]15 , which is the spontaneous transverse voltage drop induced by heat current and is known to be proportional to magnetization (Fig. 1a).…”

“…Our first-principles calculations reveal that this arises from a significantly enhanced Berry curvature associated with Weyl points near the Fermi energy 11 . As this e ect is geometrically convenient for thermoelectric power generation-it enables a lateral configuration of modules to cover a heat source 6 -these observations suggest that a new class of thermoelectric materials could be developed that exploit topological magnets to fabricate e cient, densely integrated thermopiles.Current intensive studies on thermally induced electron transport in ferromagnetic materials have opened various avenues for research on thermoelectricity and its application [12][13][14][15] . This trend has also triggered renewed interest in the anomalous Nernst effect (ANE) in ferromagnetic metals [3][4][5][6][7]15 , which is the spontaneous transverse voltage drop induced by heat current and is known to be proportional to magnetization (Fig.…”

“…Current intensive studies on thermally induced electron transport in ferromagnetic materials have opened various avenues for research on thermoelectricity and its application [12][13][14][15] . This trend has also triggered renewed interest in the anomalous Nernst effect (ANE) in ferromagnetic metals [3][4][5][6][7]15 , which is the spontaneous transverse voltage drop induced by heat current and is known to be proportional to magnetization (Fig.…”

Spin current generated by thermally driven ultrafast demagnetization

“…Conventionally, spin currents are generated by passing electrical currents through ferromagnetic materials [1][2][3][4][5] . Recently, much effort has been expended to understand the generation of spin currents by thermal gradients [6][7][8][9][10][11][12][13][14] . Yet, another route to generate spin currents is rapid demagnetization of a ferromagnetic layer by direct excitation with an ultrashort laser pulse.…”