SUB-PICOSECOND CONTROL OF NANO-MAGNETS
Lead Research Organisation:
UNIVERSITY OF EXETER
Department Name: Physics
Abstract
The data storage capacity and the speed of operation of a modern laptop computer are orders of magnitude greater than those of the first computers that occupied several large rooms. To maintain the pace of progress, both the physical bit size and the data access time must be reduced even further. Under these circumstances, the nano-magnetic technology is becoming one of the strongest players in the multibillion dollar market for high speed miniature devices for data storage and processing.This constitutes the main practical motivation for the proposed research programme which has the overall aim of gaining an ever-faster control of nanoscale magnetic structures by means of sub-picosecond optical and magnetic pulses. This will require that several issues of fundamental importance be resolved, extending our knowledge and understanding of ultrafast nano-scale magnetic dynamics to a new level.The basic phenomenon exploited in the project is the Inverse Faraday Effect due to which circularly polarised optical pulses can generate sub-picosecond pulses of magnetic field (so called photo-magnetic field), which are orders of magnitude shorter than the fastest electrical and magnetic pulses produced electronically or in ultrafast photo-diodes. The pulsed photo-magnetic field due to optical pulses from an ultrafast laser will be used to manipulate the magnetisation either directly, by using the photo-magnetic field itself, or indirectly, by converting it into pulses of the Oersted magnetic field within a novel device called a Faraday Optical Transformer. The magnetisation precession excited in magnetic thin films and nanoscale elements will be then traced magneto-optically by measuring the change of polarisation acquired by a delayed optical pulse (a probe ) upon reflection from the pumped sample. The magnetisation dynamics will be studied and imaged in both small (spin waves) and large (180 degrees reversal) amplitude regimes. A combined action of multiple pulses of photo-magnetic, Oersted and / or microwave fields will be investigated and used to optimize magnetic switching characteristics.The proposed research falls within the EPSRC's Nano World (Magnetic materials), Quantum Realm (Interaction of Light and Matter), and Miniature Machines (Photonics and Optoelectronics) priority areas.
Publications
Tkachenko V
(2010)
Spectrum and reflection of spin waves in magnonic crystals with different interface profiles
in Physical Review B
Tkachenko V
(2012)
Propagation and scattering of spin waves in curved magnonic waveguides
in Applied Physics Letters
Semenova E
(2013)
Magnetodynamical response of large-area close-packed arrays of circular dots fabricated by nanosphere lithography
in Physical Review B
Romero Vivas J
(2012)
Investigation of spin wave damping in three-dimensional magnonic crystals using the plane wave method
in Physical Review B
Montoncello F
(2013)
Asymmetry of spin wave dispersions in a hexagonal magnonic crystal
in Applied Physics Letters
Mikhaylovskiy RV
(2015)
Ultrafast optical modification of exchange interactions in iron oxides.
in Nature communications
Mikhaylovskiy R
(2013)
Low-temperature time-domain terahertz spectroscopy of terbium gallium garnet crystals
in Physical Review B
Mikhaylovskiy R
(2012)
Ultrafast inverse Faraday effect in a paramagnetic terbium gallium garnet crystal
in Physical Review B
Mikhaylovskiy R
(2010)
Negative permeability due to exchange spin-wave resonances in thin magnetic films with surface pinning
in Physical Review B
Mikhaylovskiy R
(2014)
Terahertz emission spectroscopy of laser-induced spin dynamics in TmFeO 3 and ErFeO 3 orthoferrites
in Physical Review B
Liu Y
(2010)
Optically induced magnetization dynamics and variation of damping parameter in epitaxial Co 2 MnSi Heusler alloy films
in Physical Review B
Kruglyak VV
(2010)
Imaging collective magnonic modes in 2D arrays of magnetic nanoelements.
in Physical review letters
Kruglyak V
(2010)
Magnonics
in Journal of Physics D: Applied Physics
Keatley PS
(2011)
Ultrafast magnetization dynamics of spintronic nanostructures.
in Philosophical transactions. Series A, Mathematical, physical, and engineering sciences
Keatley P
(2009)
Time- and vector-resolved magneto-optical Kerr effect measurements of large angle precessional reorientation in a 2×2µm2 ferromagnet
in Journal of Applied Physics
Dvornik M
(2013)
Magnonics - From Fundamentals to Applications
Dvornik M
(2011)
Micromagnetic method of s-parameter characterization of magnonic devices
in Journal of Applied Physics
Dvornik M
(2011)
Dispersion of collective magnonic modes in stacks of nanoscale magnetic elements
in Physical Review B
Dvornik M
(2011)
Collective magnonic modes of pairs of closely spaced magnetic nano-elements
in Journal of Applied Physics
Dmytriiev O
(2013)
Static and dynamic magnetic properties of densely packed magnetic nanowire arrays
in Physical Review B
Dmytriiev O
(2013)
Role of boundaries in micromagnetic calculations of magnonic spectra of arrays of magnetic nanoelements
in Physical Review B
Dmytriiev O
(2012)
Calculation of high-frequency permeability of magnonic metamaterials beyond the macrospin approximation
in Physical Review B
Au Y
(2013)
Direct excitation of propagating spin waves by focused ultrashort optical pulses.
in Physical review letters
Au Y
(2012)
Resonant microwave-to-spin-wave transducer
in Applied Physics Letters
Au Y
(2011)
Excitation of propagating spin waves with global uniform microwave fields
in Applied Physics Letters
Description | Definition of the research field of magnonics as the study of spin waves (waves of magnetisation, the quanta of which are called "magnons") and technology of spin wave ("magnonic") devices and metamaterials. Control of the dispersion of collective spin wave modes in arrays of magnetic nanoelements by tailoring the geometry of the constituent nanoelements. Resonant coupling of free space microwaves into spin waves with orders of magnitude shorter wavelength. Magnetically programmable magnonic valve and phase shifter. Time resolved optically pumped scanning optical microscopy (TROPSOM) and its application to imaging of spin waves excited in thin magnetic films, magnonic crystals and metamaterials by focused femtosecond laser pulses. Curvature induced anisotropy in curved magnonic waveguides. |
Exploitation Route | Continuing the research with an eventual application within consumer products. |
Sectors | Electronics,Energy |