Files

No attached file found for this publication.

Details

Authors
Abstract
Spin-dependent thermoelectric mechanisms are at the heart of the rapidly emerging field of spin caloritronics and are crucial steps in designing next generation heat management devices [1,2,3]. Highly efficient flexible spin caloritronic devices using macroscopic network films made of interconnected FM/Cu multilayered nanowires (FM = Co, NiCo, NiFe) were recently fabricated by direct electrodeposition into 3D nanoporous polymer host with no sample size limitation (see Fig. 1) [4,5]. Large magneto-thermoelectric effects have been observed and the spin-dependent Seebeck coefficients were directly obtained, being both negative (n-type) in all those systems. However, significant boost in magneto-thermoelectric performance can be expected in FM/Cu systems where the Seebeck coefficients for the spin-up and spin-down electrons have opposite signs. Such sign asymmetry is possible because the sign and magnitude of the diffusion thermopower depend strongly on the energy derivative of the density of states at the Fermi level, and has already been demonstrated in some FM dilute alloys [6,7]. Moreover, practical thermometric device required both p- and n-type elements. Here, interconnected nanowire networks made of diluted CoCr and NiCr alloys (< 7% of Cr) are studied, revealing large modifications in the magneto-transport and thermoelectric properties [8], as shown in Fig. 2. Negative anisotropic magnetoresistance have been observed, highlighting the large effect of Cr on the density of state (reversal of the resistivity spin asymmetry coefficient) [8-9]. Moreover, positive Seebeck coefficients have been obtained in interconnected nanowire networks made of diluted NiCr alloys, opening the door to magnetically tunable p-type thermoelectric devices [8] and, thus, p-n spin caloritronic junctions.
Affiliations

Citations

  • APA
  • Chicago
  • FWB

da Câmara Santa Clara Gomes, T., Marchal, N., Abreu Araujo, F., & Piraux, L. (2020). Tunable magnetoresistance and thermopower in interconnected NiCr and CoCr nanowire networks. 2020 Joint European Magnetic Symposia, Lisbon, Portugal. https://hdl.handle.net/2078.5/29341