Tunneling magneto thermo power in magnetic tunnel junction nanopillars

TL;DR

This study investigates the tunneling magneto thermo power (TMTP) in magnetic tunnel junction nanopillars, demonstrating significant spin-dependent thermoelectric effects and large TMTP variations with magnetic configuration changes.

Contribution

The paper presents experimental measurement of TMTP in CoFeB/MgO/CoFeB nanopillars, revealing large spin-dependent Seebeck coefficients and TMTP changes, advancing understanding of thermoelectric effects in magnetic tunnel junctions.

Findings

Thermo power voltages up to tens of microvolts are measured.

Thermo power signals change by up to 10 microvolts with magnetic configuration reversal.

TMTP change of up to 90% observed in the junctions.

Abstract

We study the tunneling magneto thermo power (TMTP) in CoFeB/MgO/CoFeB magnetic tunnel junction nanopillars. Thermal gradients across the junctions are generated by a micropatterned electric heater line. Thermo power voltages up to a few tens of \muV between the top and bottom contact of the nanopillars are measured which scale linearly with the applied heating power and hence with the applied temperature gradient. The thermo power signal varies by up to 10 \muV upon reversal of the relative magnetic configuration of the two CoFeB layers from parallel to antiparallel. This signal change corresponds to a large spin-dependent Seebeck coefficient of the order of 100 \muV/K and a large TMTP change of the tunnel junction of up to 90%.