Synthesis and magnetic properties of Ni/Fe shell/core nanocable arrays Xiaoru Li a,n , Peidong Li a , Guojun Song a , Zhi Peng a , Shengyu Feng b , Chuanjian Zhou b a Institute of Polymer Materials, Qingdao University, No. 308 Ningxia Road, Qingdao 266071, PR China b Key Laboratory of Special Functional Aggregated Materials, Ministry of Education, Shandong University, Jinan 250100, PR China article info Article history: Received 29 November 2013 Accepted 26 January 2014 Available online 1 February 2014 Keywords: Nanocable Nanotube Electrodeposition AAO template Magnetic Properties Magnetic materials abstract Ordered Ni/Fe shell/core structured nanocable arrays were successfully fabricated by a two-step electrodeposition process. Firstly, nickel (Ni) nanotubes were prepared by electrodeposition in nanopor- ous of anodic aluminum oxide (AAO) template. Then the AAO/Ni nanotube composite membrane was used as a secondary template to deposit Ferrum (Fe) nanowires into Ni nanotubes. The morphology and microstructure of the nanocables was characterized by scanning electron microscopy (SEM) and transmission electron microscopy (TEM). The chemical composition of the nanocables was confirmed by X-ray diffraction (XRD). Magnetization measurements revealed that Ni/Fe nanocable arrays have a lower remanence ratio than Ni nanotube and Fe nanowire arrays respectively. & 2014 Elsevier B.V. All rights reserved. 1. Introduction Attention has been paid over the last decade to the diverse physical performance of one-dimensional nanostructured materials due to their wide range of applications in optics, high-density perpendicular magnetic recording media and various sensor devices [1–5]. Com- pared with other methods such as sputtering [6], ball milling [7] and electroplating [8–10], template synthesis has been deemed to versatile approach of diverse nanostructured materials at a low cost [11–13]. Currently, ferromagnetic nanostructured materials, such as Fe [14], Co [15] and Ni [16], have been focused on research due to the unique magnetic properties [17]. Ordered ferromagnetic nanostructured arrays within a single magnetic domain size show a remarkably enhanced coercivity and a high remanence ratio, which make them prospective materials for magnetic recording media [18]. Some of the ferromagnetic nanostructured alloys can also enhance coercivity and remanence ratio. For example, Ni/Cu, Ni/Zn, and Ni/Pt nanowire arrays exhibit higher coercivity than Ni nanotubes [19–22]. However, high- density perpendicular magnetic recording media not only has high coercivity but also demagnetization and stability performance. So it is necessary to prepare demagnetization materials. However, the literatures about two ferroelectric materials composite have been rarely reported. In this paper, we report the fabrication and magnetism of Ni/Fe shell/core nanocable arrays. Magnetization measurements revealed that Ni/Fe nanocable arrays have a lower remanence ratio than Ni nanotube and Fe nanowire arrays respectively. The Ni/Fe nanocables have demagnetization performance, and they have potential appli- cations in some magnetic-high-density perpendicular magnetic recording media. Given this, we infer that the degaussing phenom- enon is related to the two magnetic materials. 2. Experimental section A porous anodic aluminum oxide (AAO) template (purchased from Whatman International Ltd.) with the pore diameter ranging from 180 to 250 nm and the depth ranging from 50 to 60 μm was used. In the experiment, Ni nanotube arrays were DC electrode- posited into the pores of AAO templates using a standard three- electrode system. The side of the AAO membrane was sputtered with a thin layer of Au as a work electrode. A platinum film was used as the counter electrode and Ag/AgCl electrode in saturated KCl solution as the reference electrode. The pH of aqueous bath containing 0.6 M NiSO 4 Á 6H 2 O, 0.4 M H 3 BO 3 and 0.3 M KCl was adjusted to 3. Electrodeposition was carried out at potential of À 0.8 V/SCE for 15 min. And Ni nanotubes can be obtained. Then AAO/Ni nanotube composite membrane was used as a “secondary template”, and Fe nanowires were deposited into the Ni nanotubes from solution of 0.5 M FeSO 4 Á 7H 2 O, 0.5 M H 3 BO 3 and 0.008 M ascorbic acid at the potential of À 1.0 V/SCE for 20 min. Scanning electron microscopy (SEM; JEOL JSM-6390LV), trans- mission electron microscopy (TEM; CM200-FEG equipped with a GIF) were used to characterize the nanotubes, nanowires, and nanocables. Selected-area electron diffraction (SAED) pattern was used to determine the structure of the nanotubes, nanowires. Contents lists available at ScienceDirect journal homepage: www.elsevier.com/locate/matlet Materials Letters 0167-577X/$ - see front matter & 2014 Elsevier B.V. All rights reserved. http://dx.doi.org/10.1016/j.matlet.2014.01.156 n Corresponding author. E-mail address: lixiaoruqdu@126.com (X. Li). Materials Letters 122 (2014) 58–61