Interplay of Peltier and Seebeck Effects in Nanoscale Nonlocal Spin Valves

Abstract

We have experimentally studied the role of thermoelectric effects in nanoscale nonlocal spin valve devices. A finite element thermoelectric model is developed to calculate the generated Seebeck voltages due to Peltier and Joule heating in the devices. By measuring the first, second, and third harmonic voltage response nonlocally, the model is experimentally examined. The results indicate that the combination of Peltier and Seebeck effects contributes significantly to the nonlocal baseline resistance. Moreover, we found that the second and third harmonic response signals can be attributed to Joule heating and temperature dependencies of both the Seebeck coefficient and resistivity.

Efficient thermal spin injection using CoFeAl nanowire

“…29 The background voltage parabolically increased with increasing bias AC current. From the fitting with the assumption, we obtained a conventional Seebeck coefficient of À22 mV K À1 .…”

Kondo physics in non-local metallic spin transport devices

“…1a). 26 , a small field-independent background (16 mO here) has been subtracted. Complete and abrupt switching between P and AP is observed, enabling determination of DR NL , the T and d dependence of which allow for extraction of a(T) and l N (T).…”

“…This non-local geometry has enabled significant advances in the understanding of spin transport in metals [4][5][6][7][8][9][10][11][12][13][14][15][16]18,22,[24][25][26][27][28][29][30][31][32][33][34][35][36][37] , but has also highlighted serious discrepancies with theory. The primary example of the latter is the surprising non-monotonicity in the temperature (T) dependence of DR NL , and thus the deduced l N , in the transparent interface limit.…”

Thermally driven spin injection from a ferromagnet into a non-magnetic metal

“…This spin current is generated because, in a ferromagnet, the Seebeck effect-which describes the generation of a voltage as a result of a temperature gradient-is spin dependent 13,14 . We studied this new source of spin currents experimentally in a non-local lateral geometry and developed a three-dimensional model that describes the heat, charge and spin transport in this geometry, enabling us to quantify this process 15 . We obtain a spin-dependent Seebeck coefficient for Permalloy of −3.8 µV K −1 , suggesting that thermally driven spin injection is a feasible alternative for electrical spin injection in, for example, spin-transfer-torque experiments 16 .…”

“…The baseline resistance R 1 b of 90 µ is in line with the calculated 95 µ . This is caused by Peltier heating and cooling of the two current-injecting contacts 15 .The negative regular spin-valve signal R 1 s can be understood as follows. Owing to the high conductivity of the copper, a fraction of the current flows into and out of the Py 1 /Cu interface electrically injecting spins.…”