Volume 77, Number 1, January 2007
Article Number 17002
Number of page(s) 5
Section Condensed Matter: Electronic Structure, Electrical, Magnetic and Optical Properties
Published online 21 December 2006
EPL, 77 (2007) 17002
DOI: 10.1209/0295-5075/77/17002

Spin mixing processes in magnetic nanostructures detected by thermoelectric measurements

L. Gravier1, S. Serrano Guisan1, G. di Domenicantionio2, M. Abid1, M. Hillenkamp2, C. Félix2 and J.-Ph. Ansermet1

1  Laboratoire de Physique des Matériaux Nanostructurés, Ecole Polytechnique Fédérale de Lausanne - CH-1015 Lausanne-EPFL, Switzerland
2  Laboratoire des Nanostructures en Matrices, Ecole Polytechnique Fédérale de Lausanne CH-1015 Lausanne-EPFL, Switzerland

received 9 June 2006; accepted in final form 3 November 2006; published January 2007
published online 21 December 2006

Spin-dependent transport properties of magnetic nanostructures have been investigated by means of magneto-thermogalvanic voltage measurements: the ac voltage response to an ac temperature oscillation is measured for various magnetic nanostructures under dc current. The samples studied include Co/Cu multilayered nanowires, homogeneous Ni nanowires and cobalt clusters embedded in copper films. The magnetic field dependence of this signal is always larger than the magneto-resistance (MR) and may be anisotropic even when the MR is not. A thermodynamic argument introduces spin mixing as the main process measured by this novel thermoelectric measurement technique. This effect is not observed in magnetite as can be justified by the absence of an accessible second spin channel.

72.25.Ba - Spin polarized transport in metals.
75.75.+a - Magnetic properties of nanostructures.
81.07.-b - Nanoscale materials and structures: fabrication and characterization.

© Europhysics Letters Association 2007