The influence of the synthesis conditions on the magnetic behaviour of the densely packed arrays of Ni nanowires in porous anodic alumina membranes

The densely packed arrays of Ni nanowires of 70 nm diameter and 6-12 mu m length were obtained via electrodeposition into porous alumina membranes (PAAMs) of 55-75 mu m thickness. The morphology, microstructure and magnetic properties between the room and liquid-helium temperature of Ni nanowires in PAAMs have been investigated using scanning electron microscopy, X-ray diffraction and vibrating sample magnetometry. The crystal structure of the Ni nanowires is fcc with (220) preferred orientation. The magnetic characteristics of the Ni nanowires in PAAMs were compared with the same characteristics of bulk Ni and with other researchers' data. The effect of the porous alumina membrane and the Ni nanowires synthesis conditions on the magnetic characteristics of Ni nanowire arrays has been studied. The coercivity reached more than 750 kOe and the squareness ratio up to 0.65 under the proposed optimal synthesis conditions for Ni nanowires. Magnetic parameters of the densely packed arrays of Ni nanowires allow using them in magnetic recording media, hard disk drives, storage systems and sensors. In addition, such structures are of considerable interest for basic research on nanomagnetism which is significantly different from the magnetic properties of bulk and thin films materials.

Automated summary

Densely packed arrays of Ni nanowires with 70 nm diameter and 6-12 μm length were obtained through electrodeposition into porous alumina membranes. The magnetic characteristics of these Ni nanowires, such as coercivity and squareness ratio, were significantly improved under optimized conditions, making them suitable for various applications in magnetic recording media and sensors. This structure is also of great interest for basic research on nanomagnetism due to its distinct magnetic properties compared to bulk and thin film materials.