Thermoelectric (TE) properties of a single nanowire (NW) are investigated in a microlab which allows the determination of the Seebeck coefficient S and the conductivity { \sigma}. A significiant influence of the magnetization of a 70 nm ferromagnetic Ni-NW on its power factor S^{ 2}{ \sigma} is observed. We detected a strong magneto thermopower effect (MTP) of about 10% and an anisotropic magneto resistance (AMR) as a function of an external magnetic field B in the order of 1%. At T = 295 K and B = 0 T we determined the absolute value of S = - (19 \pm 2) { \mu}V/K. At zero field the figure of merit ZT \approx 0.02 was calculated using the Wiedemann-Franz-law for the thermal conductivity. The thermopower S increases considerably as a function of B up to 10% at B = 0.5 T, and with a magneto thermopower of \partialS/\partialB \approx - (3.8 \pm 0,5) { \mu}V/(K.T). The AMR and MTP are related by \partials/\partialr \approx -11 \pm 1 (\partials = \partialS/S). The TE efficiency increases in a transversal magnetic field (B =0.5T) due to an enhanced power factor by nearly 20%.
Categories: cond-mat.mes-hall cond-mat.mtrl-sci