Non-Aqueous electro-deposition of novel one-dimensional Sm2Co17 nanostructures and magnetic field annealing effect on structural and magnetic properties

Abstract

Through a versatile and quite economical technique of DC electro-deposition, Sm2Co17 nanowires (NWs) have been fabricated into the nanochannels of anodic aluminum oxide (AAO) templates by using non-aqueous electrolyte. The average diameter and length of NWs are 80 nm and 3 µm respectively. The structural and magnetic properties of NWs have been investigated before and after magnetic field (MF) annealing with magnetic field strength of 1 T applied parallel to the NWs axis at temperature of 300 °C. SEM and TEM have been employed to observe the morphology of NWs after partial and full etching respectively. Deposition of SmCo alloy has been confirmed through EDX analysis whereas XRD peaks shows hexagonal closed packed (hcp-P63/mmc) as the dominant phase with (203) preferred orientation. After MF annealing the crystallinity got improved as manifested by the increase in peak sharpness. Furthermore, after the said field assisted heat treatment the magnetic parameters including coercivity (Hc) from 91 to 527 Oe for θ = 0°, from 101 to 151 Oe for θ = 90° and squareness (SQ) from 0.040 to 0.16 for θ = 0°, from 0.037 to 0.032 for θ = 90° have been observed through VSM. A switching of magnetization reversal mechanism from curling to coherent rotation has been observed after MF annealing due to the stronger inter-wire coupling which leads to parallel alignment of magnetic moments of adjacent NWs. Temperature dependent study has been carried out employing PPMS manifesting gradual increase in Hc from 67 to 440 Oe, Ms from 5.4 × 10−3 to 6.1 × 10−3 emu and SQ from 0.19 to 0.25 with the decrease in temperature up to 5 K.