Dresden 2014 – scientific programme
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TT: Fachverband Tiefe Temperaturen
TT 97: Spincaloric Transport I (organized by MA)
TT 97.5: Talk
Thursday, April 3, 2014, 17:45–18:00, HSZ 403
Magneto-Thermopower and Giant Magnetoresistance measurements on single multilayered Co-Ni/Cu nanowires — •Anna Niemann1, Tim Böhnert1, Ann-Katrin Michel1, Svenja Bäßler1, Johannes Gooth1, Katalin Neurohr2, Bence Tóth2, László Péter2, Imre Bakonyi2, and Kornelius Nielsch1 — 1Institute of Applied Physics, Universität Hamburg, Hamburg, Germany — 2Wigner Institute, Budapest, Hungary
The magneto-thermopower (MTP) is linked to the giant magnetoresistance (GMR) of individual multilayered Co-Ni/Cu nanowires with varying Cu thickness. Both magneto effects are studied temperature dependent in perpendicular magnetic fields leading to cross plane GMR effects of up to 15 % at RT. This is a typical effect size for electrodeposited nanowires. A linear dependence between thermopower S and conductivity σ of the nanowires–with the magnetic field as an implicit variable–is found at a wide temperature range (50 K to 325 K). This observation is in agreement with the Mott formula with an additional thermopower offset, which allows the estimation of the absolute Seebeck coefficient of the contact material.
The linear behavior–S vs. σ–and the Mott formula are used to calculate the energy derivative of the resistivity, which can be further correlated to the transmission function serving as a starting point in theoretical models. Magneto-thermal conductance measurements are planned to complete the characterization of the spin-caloritronic properties, in particular to validate the Wiedemann-Franz law in cross-plane GMR structures.