A5064878425- Magnetic properties of thin films
- Magnetic Properties and Applications
- Physics of Superconductivity and Magnetism
- Characterization and Applications of Magnetic Nanoparticles
- ZnO doping and properties
- Theoretical and Computational Physics
- Magneto-Optical Properties and Applications
- Quantum and electron transport phenomena
- Semiconductor materials and devices
- Advanced Memory and Neural Computing
- Multiferroics and related materials
- Magnetic and transport properties of perovskites and related materials
- Cellular Automata and Applications
- Advanced Data Storage Technologies
- Quantum-Dot Cellular Automata
- Advanced Electron Microscopy Techniques and Applications
- Surface and Thin Film Phenomena
- Force Microscopy Techniques and Applications
- Magnetic Properties of Alloys
- Ion-surface interactions and analysis
- Magnetic Field Sensors Techniques
- Microfluidic and Bio-sensing Technologies
- Anodic Oxide Films and Nanostructures
- Advanced Condensed Matter Physics
- Ferroelectric and Piezoelectric Materials
University of Cambridge
2015-2024
Lancaster University
2021
TU Dortmund University
2021
University of Leeds
2021
Cardiff University
2012-2014
University of Minnesota
2012-2014
University of Exeter
2014
Conference Board
2013
Micro Magnetics (United States)
2013
Canadian Standards Association
2013
"Spintronics," in which both the spin and charge of electrons are used for logic memory operations, promises an alternate route to traditional semiconductor electronics. A complete architecture can be constructed, uses planar magnetic wires that less than a micrometer width. Logical NOT, logical AND, signal fan-out, cross-over elements each have simple geometric design, they integrated together into one circuit. An additional element data input allows information written domain-wall circuits.
The magnetic properties of deep submicron circular nanomagnets fabricated by high-resolution electron beam lithography from Supermalloy $({\mathrm{Ni}}_{80}{\mathrm{Fe}}_{14}{\mathrm{Mo}}_{5})$ have been studied as a function both diameter (500--55 nm) and thickness (6--15 nm). A high sensitivity magneto-optical method has used to measure the hysteresis loops these nanomagnets. An experimental phase diagram in thus produced which identifies vortex single-domain phase. two phases agree well...
All computers process information electronically. A processing method based on magnetism is reported here, in which networks of interacting submicrometer magnetic dots are used to perform logic operations and propagate at room temperature. The states signaled by the magnetization direction single-domain dots; couple their nearest neighbors through magnetostatic interactions. Magnetic solitons carry networks, an applied oscillating field feeds energy into system serves as a clock. These offer...
An all-metallic submicrometer device is demonstrated experimentally at room temperature that performs logical NOT operations on magnetic logic signals. When this two-terminal ferromagnetic structure incorporated into a feedback loop, the junction frequency division operation an applied oscillating field. Up to 11 of these junctions are then directly linked together create shift register.
Nanometre scale magnetic particles (`nanoelements' or `nanomagnets') form a rich and rapidly growing new area in condensed matter physics, with many potential applications data storage technology field sensing. This paper reviews an extensive study into the influence of shape on properties nanomagnets size range 35-500 nm. Elliptical, triangular, square, pentagonal circular geometries have all been considered. It is shown that size, thickness geometric play vital role determining properties....
The control of magnetic order in nanoscale devices underpins many proposals for integrating spintronics concepts into conventional electronics. A key challenge lies finding an energy-efficient means control, as power dissipation remains important factor limiting future miniaturization integrated circuits. One promising approach involves magnetoelectric coupling magnetostrictive/piezoelectric systems, where induced strains can bear directly on the anisotropy. While such processes have been...
We demonstrate movement of a head-to-head domain wall through magnetic nanowire simply by passing an electrical current the and without any external field applied. The effect depends on sense magnitude allows direct propagation walls complex shapes, contrary to case induced propagation. efficiency this mechanism has been evaluated effective force acting found equal 0.88x10-9 N.A-1.
We have studied the process by which in-plane magnetization of an ultrathin (4–11 ML) epitaxial iron film reverses under action external magnetic field. Kerr effect measurements reveal a small uniaxial anisotropy superimposed on cubic magnetocrystalline greatly influences reversal. In addition, we find that depending upon field orientation, reversal can proceed either via ‘‘1-jump’’ mechanism, sweeping 180° domain walls and gives classic square hysteresis loop, or ‘‘2-jump’’ 90° at two...
We present a treatment of polarized light analysis and noise sources relevant to magneto-optical Kerr effect (MOKE) measurements magnetic nanostructures give performance details our state-of-the-art MOKE magnetometer in these terms. By considering the various signal contributions, we are able determine experimental conditions for optimal dynamic range signal-to-noise ratio. A description instrument includes novel facility locate by producing susceptibility map sample surface. The is...
Control of the motion domain walls in magnetic nanowires is at heart various recently proposed three-dimensional (3D) memory devices. However, fabricating 3D nanostructures extremely complicated using standard lithography techniques. Here we show that highly pure with aspect-ratios ~100 can be grown focused electron-beam-induced-deposition. By combining micromanipulation, Kerr magnetometry and force microscopy, determine magnetisation reversal wires occurs via nucleation propagation walls....
The design of complex, competing effects in magnetic systems-be it via the introduction nonlinear interactions1-4, or patterning three-dimensional geometries5,6-is an emerging route to achieve new functionalities. In particular, through geometries and curvature, intrastructure properties such as anisotropy chirality, both geometry-induced intrinsic, can be directly controlled, leading a host physics functionalities, chiral spin states7, ultrafast domain wall dynamics8-10 textures with...
A novel magneto-optical method has been used to probe the internal magnetic energy surface in $150\ifmmode\times\else\texttimes\fi{}150\ifmmode\times\else\texttimes\fi{}15{\mathrm{nm}}^{3}$ square ${\mathrm{Ni}}_{80}{\mathrm{Fe}}_{14}{\mathrm{Mo}}_{5}$ (``supermalloy'') nanomagnets which were fabricated by electron beam lithography. strong fourfold symmetric anisotropy field of strength $365\ifmmode\pm\else\textpm\fi{}20\mathrm{Oe}$ is found, confirms a recent prediction appearance...
The magnetic switching of a continuous Permalloy film is artificially modified by lithographically structuring an antidot array. antidots introduce spatially variant shape anisotropy field that competes with the intrinsic uniaxial film. This results in well-defined periodic domain structure at remanence as observed scanning Kerr microscopy, and which could be significant for high-density data storage. A micromagnetic calculation explains indicates optimum conditions storage applications.
The potential experienced by transverse domain walls (TDWs) in the vicinity of asymmetric constrictions or protrusions thin Permalloy nanowires is probed using spatially resolved magneto-optical Kerr effect measurements. Both types traps are found to act as pinning centers for DWs. strength depend on trap type well chirality incoming DW; both seen either wells barriers, also depending DW. Micromagnetic simulations have been performed that good qualitative agreement with experimental results.
The successful fabrication of ultra‐thin films CoFeB/Pt with strong perpendicular magnetic anisotropy and antiferromagnetic interfacial interlayer coupling on flexible polyimide substrates is demonstrated. Despite an increased surface roughness defect density the substrate, single layers CoFeB still show sharp coercive switching. Magnetic Kerr imaging shows that magnetization reversal dominated by a greater nucleation sites than identical film grown Si. These maintain their characteristics...
Using numerical micromagnetics we have studied the ground state magnetization distribution of square planar ferromagnetic elements (“nanostructures”). As element size is reduced from 250 to 2 nm at constant thickness (2–35 nm), find that undergoes up three phase transitions involving as many different near single domain states. One these analogous reorientation transition observed in continuous ultrathin magnetic films.