Super-giant magnetoresistance at room-temperature in copper nanowires due to magnetic field modulation of potential barrier heights at nanowire-contact interfaces

Abstract

We have observed a super-giant (∼10,000,000%) negative magnetoresistance at 39 mT field in Cu nanowires contacted with Au contact pads. In these nanowires, potential barriers form at the two Cu/Au interfaces because of Cu oxidation that results in an ultrathin copper oxide layer forming between Cu and Au. Current flows when electrons tunnel through, and/or thermionically emit over, these barriers. A magnetic field applied transverse to the direction of current flow along the wire deflects electrons toward one edge of the wire because of the Lorentz force, causing electron accumulation at that edge and depletion at the other. This lowers the potential barrier at the accumulated edge and raises it at the depleted edge, causing a super-giant magnetoresistance at room temperature.

Preparation of CuO Nanorods by Thermal Oxidation in Ozone Ambient

“…The characteristics of nanocrystalline semiconductor particles have drawn considerable interest in recent years because of their special properties such as a large surface-to-volume ratio, increased activity, special electronic properties and unique optical properties compared to those of the bulk materials [1][2][3]. Copper oxide is a p-type multifunctional semiconductor with a narrow band gap (Eg ~ 1.2 eV in bulk), and has been recognized as an industrially important and exotic material for a variety ________ of practical applications [4][5][6]. For practical applications based on CuO nanomaterials, the good alignment and uniformity of the materials are required.…”

Non-contact Local Conductivity Measurement of Metallic Nanowires Based on Semi-near-field Reflection of Microwave Atomic Force Microscopy

“…Metallic nanowires have been promising functional materials for various applications, such as magnetic data storage media [1][2][3], giant magnetoresistance nanowires [4,5], metamaterials [6][7][8], thermoelectric power conversion [9,10], chemical or biological sensors [11,12], and transparent electrodes [13]. Conductivity is one of the most valuable properties for the application of metallic nanowires.…”

Non-contact local conductivity measurement of metallic nanowires based on semi-near-field reflection of microwave atomic force microscopy

“…etallic nanowires continue to be promising functional materials for various applications, such as magnetic data storage media, [1][2][3] giant magnetoresistant nanowires, 4,5) metamaterials, [6][7][8] thermoelectric power conversion, 9,10) chemical or biological sensors, 11,12) and transparent electrodes. 13) Conductivity is one of the most valuable properties for applications that use metallic nanowires.…”