The effect of different Fe concentrations on the structural and magnetic properties of near surface superparamagnetic Ni1-xFex nanoparticles in SiO2 made by dual low energy ion implantation
Grant VM Williams, John Kennedy, Peter P Murmu, Sergey Rubanov, Shen Chong
JOURNAL OF MAGNETISM AND MAGNETIC MATERIALS | ELSEVIER | Published : 2019
Structural and magnetic measurements were performed on SiO2 films containing near-surface Ni1−xFex superparamagnetic nanoparticles made by low energy ion implantation into SiO2 with the same Ni fluences of 2 × 1016 at./cm2 and two different Fe fluences so that x = 0.47 and x = 0.20. The x = 0.47 films had larger nanoparticles, a higher fraction of ordered moments in the nanoparticle cores, and thinner spin-disordered shells. The nanoparticle core spin-stiffnesses were slightly higher for x = 0.20 and smaller than that expected for bulk Ni1−xFex for both Fe concentrations. There was no evidence for magnetic dipole interactions between the nanoparticles that have been reported in compressed su..View full abstract
Awarded by Ministry of Business, Innovation and Employment (MBIE) Smart Idea Fund
We acknowledge funding from the MacDiarmid Institute for Advanced Materials and Nanotechnology and the Ministry of Business, Innovation and Employment (MBIE) Smart Idea Fund (C05X1712).