Fabrication of surface magnetic nanoclusters using low energy ion implantation and electron beam annealing

Abstract

Magnetic nanoclusters have novel applications as magnetic sensors, spintronic and biomedical devices, as well as applications in more traditional materials such as high-density magnetic storage media and high performance permanent magnets. We describe a new synthesis protocol which combines the advantages of ion implantation and electron beam annealing (EBA) to produce surface iron nanoclusters. We compare the structure, composition and magnetic properties of iron nanoclusters fabricated by low dose 15 keV Fe implantation into SiO(2) followed by 1000 °C EBA or furnace annealing. Atomic force microscopy (AFM) and high resolution transmission electron microscopy (HRTEM) images together with superconducting quantum interference device (SQUID) magnetometry measurements show that only EBA leads to the rapid formation of surface crystalline Fe spherical nanoclusters, showing magnetic moments per Fe atom comparable to that of bulk bcc Fe and superparamagnetic properties. We propose a fabrication mechanism which includes e-beam enhanced desorption of SiO(2). This method has potential for fabricating nanoscale magnetic sensors integrated in microelectronic devices.

Structural, electronic and magnetic properties of Er implanted ZnO thin films

“…40 keV Er ions were implanted into polycrystalline ZnO thin films using GNS low-energy ion implanter [9]. The ZnO films were prepared using ion beam sputtering system with a thickness around 150 nm [10].…”

“…Here onwards, the samples annealed in high vacuum and air atmosphere are labeled as ''HVA 650°C'' and ''Oxy 650°C'', respectively. Rutherford backscattering spectrometry (RBS) measurements were conducted using a 1 mm collimated 2 MeV 4 He + beam [9,12]. The backscattered particles were collected using a Si surface barrier detector placed at a scattering angle of 165°.…”

Microfabricated Magnetic Structures for Future Medicine: From Sensors to Cell Actuators

“…Fabrication methods are still being actively developed. Recently, Kennedy et al demonstrated a method for depositing magnetic nanoclusters surface using ion implantation on dielectric SiO 2 followed by electron beam annealing at 1000°C [65]. The nanoclusters with particles ranging from 5 to 40 nm were obtained.…”

Synthesis of magnetic nanoparticles by low-energy dual ion implantation of iron and nickel into silicon dioxide followed by electron beam annealing

“…The various conventional methods to synthesise nanoparticles include chemical synthesis [5], polyol synthesis [6], laser ablation [7], and arc discharge [8]. Ion implantation is a novel method that could potentially be used to synthesise magnetic nanoparticles with unique properties tailored to suit different applications [9][10][11]. Near-surface iron nanoparticles have previously been synthesised in SiO 2 films using low-energy ion implantation followed by electron beam annealing [9,10].…”