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Nonlinear thermoelectric effects in high-field superconductor-ferromagnet tunnel junctions

Kolenda, Stefan; Machon, Peter; Beckmann, Detlef; Belzig, Wolfgang

Abstract (englisch): Background: Thermoelectric effects result from the coupling of charge and heat transport and can be used for thermometry, cooling and harvesting of thermal energy. The microscopic origin of thermoelectric effects is a broken electron–hole symmetry, which is usually quite small in metal structures. In addition, thermoelectric effects decrease towards low temperatures, which usually makes them vanishingly small in metal nanostructures in the sub-Kelvin regime. Results: We report on a combined experimental and theoretical investigation of thermoelectric effects in superconductor/ferromagnet hybrid structures. We investigate the dependence of thermoelectric currents on the thermal excitation, as well as on the presence of a dc bias voltage across the junction. Conclusion: Large thermoelectric effects are observed in superconductor/ferromagnet and superconductor/normal-metal hybrid structures. The spin-independent signals observed under finite voltage bias are shown to be reciprocal to the physics of superconductor/normal-metal microrefrigerators. The spin-dependent thermoelectric signals in the linear regime are due to the coupling of spin and heat transport, and can be used to design more efficient refrigerators.

Zugehörige Institution(en) am KIT Institut für Nanotechnologie (INT)
Publikationstyp Zeitschriftenaufsatz
Jahr 2016
Sprache Englisch
Identifikator DOI: 10.3762/bjnano.7.152
ISSN: 2190-4286
URN: urn:nbn:de:swb:90-616198
KITopen ID: 1000061619
HGF-Programm 43.21.02; LK 01
Erschienen in Beilstein journal of nanotechnology
Band 7
Seiten 1579-1585
Schlagworte spintronics, superconductor-ferromagnet hybrids, thermoelectricity
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