Magnetic control of flexible thermoelectric devices based on macroscopic 3D interconnected nanowire networks

Abstract

Spin-related effects in thermoelectricity can be used to design more efficient refrigerators and offer novel promising applications for the harvesting of thermal energy. The key challenge is to design structural and compositional magnetic material systems with sufficiently high efficiency and power output for transforming thermal energy into electric energy and vice versa. Here, the fabrication of large-area 3D interconnected Co/Cu nanowire networks is demonstrated, thereby enabling the controlled Peltier cooling of macroscopic electronic components with an external magnetic field. The flexible, macroscopic devices overcome inherent limitations of nanoscale magnetic structures due to insufficient power generation capability that limits the heat management applications. From properly designed experiments, large spin-dependent Seebeck and Peltier coefficients of $-9.4$ $\mu$V/K and $-2.8$ mV at room temperature, respectively. The resulting power factor of Co/Cu nanowire networks at room temperature ($\sim 7.5$ mW/K${}^2$m) is larger than those of state of the art thermoelectric materials, such as BiTe alloys and the magneto-power factor ratio reaches about 100\% over a wide temperature range. Validation of magnetic control of heat flow achieved by taking advantage of the spin-dependent thermoelectric properties of flexible macroscopic nanowire networks lay the groundwork to design shapeable thermoelectric coolers exploiting the spin degree of freedom.

arXiv comment11 pages, 7 figures

References in corpus (13)

• Spin Caloritronics
• Spin Seebeck insulator
• Observation of the Spin-Seebeck Effect in a Ferromagnetic Semiconductor
• Thermally driven spin injection from a ferromagnet into a non-magnetic metal
• Seebeck Effect in Magnetic Tunnel Junctions
• Thermal Spin-Transfer Torques in Magnetoelectronic Devices
• Cooling and heating with electron spins: Observation of the spin Peltier effect
• Tunneling magneto thermo power in magnetic tunnel junction nanopillars
• CPP Magnetoresistance of Magnetic Multilayers: A critical review
• Spin-dependent Seebeck coefficients of Ni_{80}Fe_{20} and Co in nanopillar spin valves
• Giant thermal spin torque assisted magnetic tunnel junction switching
• Magnetothermopower and magnetoresistance of single Co-Ni/Cu multilayered nanowires
• Spin Seebeck power generators