Giant Magnetoresistance and Magneto-Thermopower in 3D Interconnected Ni(x)Fe(1−x)/Cu Multilayered Nanowire Networks

The versatility of the template-assisted electrodeposition technique to fabricate complex three-dimensional networks made of interconnected nanowires allows one to easily stack ferromagnetic and non-magnetic metallic layers along the nanowire axis. This leads to the fabrication of unique multilayered nanowire network films showing giant magnetoresistance effect in the current-perpendicular-to-plane configuration that can be reliably measured along the macroscopic in-plane direction of the films. Moreover, the system also enables reliable measurements of the analogous magneto-thermoelectric properties of the multilayered nanowire networks. Here, three-dimensional interconnected Ni [Formula: see text] Fe [Formula: see text] /Cu multilayered nanowire networks (with [Formula: see text]) are fabricated and characterized, leading to large magnetoresistance and magneto-thermopower ratios up to 17% and −25% in Ni [Formula: see text] Fe [Formula: see text] /Cu, respectively. A strong contrast is observed between the amplitudes of magnetoresistance and magneto-thermoelectric effects depending on the Ni content of the NiFe alloys. In particular, for the highest Ni concentrations, a strong increase in the magneto-thermoelectric effect is observed, more than a factor of 7 larger than the magnetoresistive effect for Ni [Formula: see text] Fe [Formula: see text] /Cu multilayers. This sharp increase is mainly due to an increase in the spin-dependent Seebeck coefficient from −7 µV/K for the Ni [Formula: see text] Fe [Formula: see text] /Cu and Ni [Formula: see text] Fe [Formula: see text] /Cu nanowire arrays to −21 µV/K for the Ni [Formula: see text] Fe [Formula: see text] /Cu nanowire array. The enhancement of the magneto-thermoelectric effect for multilayered nanowire networks based on dilute Ni alloys is promising for obtaining a flexible magnetic switch for thermoelectric generation for potential applications in heat management or logic devices using thermal energy.