Magnetic behavior of NiCu nanowire arrays: Compositional, geometry and temperature dependence

Abstract

Arrays of Ni 100Àx Cu x nanowires ranging in composition 0 x 75, diameter from 35 to 80 nm, and length from 150 nm to 28 lm have been fabricated by electrochemical co-deposition of Ni and Cu into self-ordered anodic aluminum oxide membranes. As determined by X-ray diffraction and Transmission Electron Microscopy, the crystalline structure shows fcc cubic symmetry with [111] preferred texture and preferential Ni or Cu lattice depending on the composition. Their magnetic properties such as coercivity and squareness have been determined as a function of composition and geometry in a Vibrating Sample Magnetometer in the temperature range from 10 to 290 K for applied magnetic fields parallel and perpendicular to the nanowires axis. Addition of Cu into the NiCu alloy up to 50% enhances both parallel coercivity and squareness. For the higher Cu content, these properties decrease and the magnetization easy axis becomes oriented perpendicular to the wires. In addition, coercivity and squareness increase by decreasing the diameter of nanowires which is ascribed to the increase of shape anisotropy. The temperature dependent measurements reflect a complex behavior of the magnetic anisotropy as a result of energy contributions with different evolution with temperature. V

Magnetic reversal modes in cylindrical nanostructures: from disks to wires

“…1 b.1), the H c and m r decease, presenting similar values in both directions. However even for the smallest aspect ratios (lower than 1) our results evidence the existence of an easy magnetization axis along the parallel direction for all samples, contrary to the reported in the literature 41 , 42 . This behavior can be attributed to the high dipolar interactions exhibited between the neighbor Ni segments 43 .…”

Geometry-Dependent Magnetic Properties of Ising-Type Multisegment Nanowires

“…3, it can also be seen that the H C , as well as the M r /M s , decreases with increasing l. We also observed that the H C and M r /M S were significantly influenced by varying the d of the nanowire. Similar results have been reported in multisegment nanowires such as CoNiP [36], Ni/Cu [37], NiCu/Cu [39], Co/Ni [40], Co/Fe [41], and Ni/Fe [42].…”

“…Because MNs show novel and interesting properties with a specific structure, they have been studied to investigate the dependence of geometrical parameters such as the wire diameter [36][37][38], segment thicknesses [28,[37][38][39][40][41][42], and aspect ratio [43,44] on the magnetic properties. Moreover, the hysteresis properties of the Ising-type multisegment nanowire with alternating magnetic spin-1/2 and spin-1 segments were investigated by using the EFT with correlations.…”

Tailoring magnetic properties in arrays of pulse-electrodeposited Co nanowires: The role of Cu additive

“…So far, single element, binary alloy, ternary alloy and multilayered magnetic NWs such as Co, Ni, Fe, NiCu, FeCo, CoCu, CoNi, FeCoCu and CoNi/Cu have been prepared using the electrodeposition technique [12][13][14][15][16][17][18][19][20]. Having paid particular attention to both the binary alloy and multilayered NWs due their potential application in the magnetoresistive and thermoelectric devices at the nanoscale, they show considerable amounts of magnetoresistance and magnetothermopower, which in turn, can compete with those of the conventional counterpart materials [18,20,21].…”