EXTREMAG – Home

What is EXTREMAG?

• The Exeter time-resolved magnetism (EXTREMAG) facility is an ultrafast laser facility for ultrafast/high frequency magnetism characterisation. Laser pulse or microwave stimulated pump-probe techniques are available within a variety of experiments with low temperature, high magnetic field, and high resolution microscopy capabilities.
• EXTREMAG is located in the Department of Physics and Astronomy at the University of Exeter in two adjacent basement labs that were refurbished to accommodate the facility in a dedicated, stable environment for sensitive optical measurements. EXTREMAG is available to users from academia and industry, as well as local users at the University of Exeter.
• EXTREMAG will make Exeter’s expertise in ultrafast optical measurements available in fully supported experiments. The Senior Experimental Officer/Facility Manager will set-up and initiate measurements. Where appropriate, training and guidance will be provided with the aim for users to carry out routine measurements independently.

The Free Space Lab B2 with the time-resolved scanning Kerr microscope in the foreground.  Lab B3 now accommodates a THz spectrometer, a MicrostatHe-R cryostat, and a Spectromag SM4000 10 T superconducting magnet (not featured in this image).  The Free Space Lab will be used for THz spectroscopy and imaging, and all-optical pump-probe Kerr measurements with low temperature and high magnetic field capability.  Laser beams enter B2 from the laser enclosure in the adjacent lab via interlocked ports (right).

Why use EXTREMAG?

• The use of high frequency measurement techniques in magnetism research has increased enormously because the fundamental timescales for resonance and relaxation lie in the sub-nanosecond regime. Time-resolved magneto-optical measurement techniques offer a unique blend of high temporal and spatial resolution within table-top experiments. EXTREMAG is a dedicated facility for the time-resolved measurement of ferromagnetic, ferrimagnetic, and antiferromagnetic materials in bulk, thin film, or 2-dimensional forms. Capability also extends to measurement of sub-micron prototype wafer level devices in response to DC, pulsed, or microwave stimulus including spintronic, magnonic and acoustic based systems.

The user space of Microscopy Lab B3 with the low temperature wide field Kerr microscope in the foreground.  B3 now accommodates the MicrostatMO 5T superconducting magnet (not featured in this image).  The lasers are located in the rear third of the lab behind an interlocked partition through which the lasers pass via interlocked ports into the user space of B3.

Users and benefits of EXTREMAG

• There are approximately 200 permanent academic researchers in UK universities and national laboratories working in the field of magnetism.
• The EXTREMAG facility will be available to UK-based users initially, and will welcome international users as the facility develops.
• Recent UK research highlights include the stabilization of novel magnetic textures such as droplets and skyrmions, manipulation of spin currents in antiferromagnets, and integration of magnetic materials with superconductors for exploitation of spin within quantum technologies.
• EXTREMAG will benefit the UK magnetism community by providing improved understanding of nanoscale magnetism on ultrafast timescales.  This knowledge may then be exploited within information technology and non-volatile data storage for low-power computation, while advancing the understanding of permanent magnet materials will underpin the development of green energy technologies.

The optical table configuration of adjacent Labs B2 (left) and B3 (right). The lasers are located in the enclosure in the rear third of Lab B3 and will be the light source for the user space of both labs. Image courtesy of Peter Savage.

Objectives of the original EPSRC project

• To procure a femtosecond laser system and measurement apparatus optimized for the study of magnetic and spintronic systems.
• To appoint an experienced scientific officer to maintain the facility, configure the apparatus for different types of measurement, and support external users.
• To install the equipment and demonstrate capability for magneto-optical pump-probe measurements, THz spectroscopy and microscopy, and time resolved Kerr microscopy, in a range of sample environments identified through consultation with external users.
• To request and evaluate proposals for user experiments from the UK and beyond, allocate time at the facility according to scientific merit, and monitor their success
• To promote the facility within the magnetism and spintronics community, publicise its achievements, and host a facility users meeting at the end of an initial 2 year period.

The interlocked Laser Enclosure at the rear of B3 accommodates the Fidelity (right), Monaco (center), and Opera-F (left) lasers.