Nonlinear Seebeck effect in Ni81Fe19|Pt at room temperature
Abstract
The nonlinear Seebeck effect, nonlinear conversion of a temperature gradient into an electric current, was observed at room temperature. Based on a second-harmonic lock-in method combined with an a.c. temperature gradient, ∇T, we measured a nonlinear Seebeck voltage in NiFe|Pt bilayers at 300 K, the amplitude of which increases in proportion to (∇T)2. We also observed that the nonlinear Seebeck voltage increases as the sample length along the ∇T direction decreases, showing a characteristic scaling law distinct from the conventional linear Seebeck effect. We developed a phenomenological model for the nonlinear Seebeck effect incorporating the spin-current induced modulation of the Seebeck coefficient, which well reproduces the experimental results.
Article Details
Journal Info
Applied Physics Letters
American Institute of Physics
Authors (4)
Y. Hirata
Department of Applied Physics, The University of Tokyo 1 , Tokyo 113-8656,
T. Kikkawa
Department of Applied Physics, The University of Tokyo 1 , Tokyo 113-8656,
H. Arisawa
Department of Applied Physics, The University of Tokyo 2 , 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-8656,
E. Saitoh
Department of Applied Physics, The University of Tokyo 2 , 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-8656,