The magnetothermopower and the magnetoresistance of single Co-Ni/Cu multilayered nanowires with various thicknesses of the Cu spacer are investigated. Both kinds of measurement have been performed as a function of temperature (50 K to 325 K) and under applied magnetic fields perpendicular to the nanowire axis, with magnitudes up to -15 % at room temperature. A linear relation between thermopower S and electrical conductivity σ of the nanowires is found, with the magnetic field as an implicit variable. Combining the linear behavior of the S vs. σ and the Mott formula, the energy derivative of the resistivity has been determined. In order to extract the true nanowire materials parameters from the measured thermopower, a simple model based on the Mott formula is employed to distinguish the individual thermopower contributions of the sample. By assuming that the non-diffusive thermopower contributions of the nanowire can be neglected, it was found that the magnetic field induced changes of thermopower and resistivity are equivalent. The emphasis in the present paper is on the comparison of the magnetoresistance and magnetothermopower results and it is found that the same correlation is valid between the two sets of data for all samples, irrespective of the relative importance of the giant magnetoresistance or anisotropic magnetoresistance contributions in the various individual nanowires.

Thermoelectric (TE) measurements have been performed on the workhorses of today's data storage devices, exhibiting either the giant or the anisotropic magnetoresistance effect (GMR and AMR). The temperature‐dependent (50–300 K) and magnetic field‐dependent (up to 1 T) TE power factor (PF) has been determined for several CoNi alloy nanowires with varying Co:Ni ratios as well as for CoNi/Cu multilayered nanowires with various Cu layer thicknesses, which are all synthesized via a template‐assisted electrodeposition process. A systematic investigation of the resistivity, as well as the Seebeck coefficient, is performed for CoNi alloy nanowires and CoNi/Cu multilayered nanowires. At room temperature, measured values of TE PFs up to 3.6 mW K−2 m−1 for AMR samples and 2.0 mW K−2 m−1 for GMR nanowires are obtained. Furthermore, the TE PF is found to increase by up to 13.1% for AMR CoNi alloy nanowires and by up to 52% for GMR CoNi/Cu samples in an external applied magnetic field. The magnetic nanowires exhibit TE PFs that are of the same order of magnitude as TE PFs of BiSbSeTe based thermoelectric materials and, additionally, give the opportunity to adjust the TE power output to changing loads and hotspots through external magnetic fields.