Magnetothermopower of Fe / Cr superlattices

Conover, M. J.; Brodsky, M. B.; Mattson, J. E.; Sowers, C. H.; Bader, S. D.

doi:10.1016/0304-8853(91)90255-9

Cited by 51 publications

(24 citation statements)

References 22 publications

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“…In order to improve ZT either S should be increased or the Lorenz number L = κ/σT should be decreased as ZT = S 2 /L. Measurements of the magneto-thermopower [6,7,8,9,10,11,12,13,14,15] and of the magneto-thermal conductivity [13][14][15]16] of GMR material systems have been carried out to evaluate the nature of spin-dependent scattering responsible for the GMR.…”

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confidence: 99%

Magnetothermoelectric figure of merit of Co/Cu multilayers

Krzysteczko

Liebing

et al. 2014

Appl. Phys. Lett.

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The switching of the magnetization configurations of giant magnetoresistance multilayer stacks not only changes the electric and thermal conductivities, but also the thermopower. We study the magnetotransport and the magneto-thermoelectric properties of Co/Cu multilayer devices in a lateral thermal gradient. We derive values of the Seebeck coefficient, the thermoelectric figure of merit, and the thermoelectric power factor. The Seebeck coefficient reaches values up to -18 µV/K at room temperature and shows a magnetic field dependence up to 28.6 % upon spin reversal.In combination with thermal conductivity data of the same Co/Cu stack, we find a spin dependence of the thermoelectric figure of merit of up to 65 %. Furthermore, a spin dependence of the power factor of up to 110 % is derived.

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confidence: 99%

Magnetothermoelectric figure of merit of Co/Cu multilayers

Krzysteczko

Liebing

et al. 2014

Appl. Phys. Lett.

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“…1 The mismatch of spin currents at the interface between two ferromagnetic (F) electrodes with antiparallel spin polarizations produces a larger contact resistance than a junction with parallel polarizations, leading to tunneling magnetoresistance in F-F junctions 2,3 and giant magnetoresistance (GMR) in multilayer structures. 4,5 Systems displaying GMR have shown other magnetotransport effects including substantial magnetothermopower [6][7][8][9][10][11][12][13][14][15] with a strong temperature dependence. Thermoelectric effects have also been discussed in the context of spin injection across a ferromagnetic-paramagnetic junction.…”

Section: Introductionmentioning

confidence: 99%

Giant magnetothermopower of magnon-assisted transport in ferromagnetic tunnel junctions

McCann

Falko

2002

Phys. Rev. B

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We present a theoretical description of the thermopower due to magnon-assisted tunneling in a mesoscopic tunnel junction between two ferromagnetic metals. The thermopower is generated in the course of thermal equilibration between two baths of magnons, mediated by electrons. For a junction between two ferromagnets with antiparallel polarizations, the ability of magnon-assisted tunneling to create thermopower SAP depends on the difference between the size Π ↑,↓ of the majority and minority band Fermi surfaces and it is proportional to a temperature dependent factor (kBT /ωD) 3/2 where ωD is the magnon Debye energy. The latter factor reflects the fractional change in the net magnetization of the reservoirs due to thermal magnons at temperature T (Bloch's T 3/2 law). In contrast, the contribution of magnon-assisted tunneling to the thermopower SP of a junction with parallel polarizations is negligible. As the relative polarizations of ferromagnetic layers can be manipulated by an external magnetic field, a large differenceresults in a magnetothermopower effect. This magnetothermopower effect becomes giant in the extreme case of a junction between two half-metallic ferromagnets, ∆S ∼ −kB/e.

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“…Experiments show a linear behavior between thermopower S and electrical conductivity σ [1][2][3][4][5][6][7][8][9][10][11][12][13][14] , with the magnetic field as an implicit variable, in metals with anisotropic magnetoresistance (AMR) [15][16][17] or giant magnetoresistance (GMR) 18,19 effects. Comparing this linear relation to the Mott formula 20 , which describes the diffusive part of the thermopower, a direct proportionality between S and σ is predicted in materials with negligible nondiffusive contributions.…”

Section: Introductionmentioning

confidence: 99%

“…The magnetic-field dependence of S in materials that show AMR or GMR effects is explained either by two spin-dependent Seebeck coefficients 1,2 or through the Mott formula using the resistivity instead of the electrical conductivity of the sample [1][2][3][4][5][6][7][8][9] . The latter approach has been applied by Conover et al 3 and is used to predict equivalent MTP and magnetoresistance (MR) behavior.…”

Section: Introductionmentioning

confidence: 99%

Magnetothermopower and magnetoresistance of single Co-Ni/Cu multilayered nanowires

et al. 2014

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The magnetothermopower and the magnetoresistance of single Co-Ni/Cu multilayered nanowires with various thicknesses of the Cu spacer are investigated. Both kinds of measurement have been performed as a function of temperature (50 K to 325 K) and under applied magnetic fields perpendicular to the nanowire axis, with magnitudes up to -15 % at room temperature. A linear relation between thermopower S and electrical conductivity σ of the nanowires is found, with the magnetic field as an implicit variable. Combining the linear behavior of the S vs. σ and the Mott formula, the energy derivative of the resistivity has been determined. In order to extract the true nanowire materials parameters from the measured thermopower, a simple model based on the Mott formula is employed to distinguish the individual thermopower contributions of the sample. By assuming that the non-diffusive thermopower contributions of the nanowire can be neglected, it was found that the magnetic field induced changes of thermopower and resistivity are equivalent. The emphasis in the present paper is on the comparison of the magnetoresistance and magnetothermopower results and it is found that the same correlation is valid between the two sets of data for all samples, irrespective of the relative importance of the giant magnetoresistance or anisotropic magnetoresistance contributions in the various individual nanowires.

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Magnetothermopower of Fe / Cr superlattices

Cited by 51 publications

References 22 publications

Magnetothermoelectric figure of merit of Co/Cu multilayers

Magnetothermoelectric figure of merit of Co/Cu multilayers

Giant magnetothermopower of magnon-assisted transport in ferromagnetic tunnel junctions

Magnetothermopower and magnetoresistance of single Co-Ni/Cu multilayered nanowires

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