Nanomagnetism & Spintronics
At NPL we develop methods, instrumentation and magnetic artefacts for quantitative measurements of magnetic parameters and phenomena in nanoscale systems.
In low dimensional systems, magnetic properties of materials change dramatically compared to those in bulk and the 'quantumness' of magnetic phenomena starts to play a critical role. Thus, the quantum nature of the spin should be ultimately considered and quantum measurement techniques should be developed.
Such magnetic quantities as magnetisation, Curie temperature, exchange constant and domain wall width are significantly altered already in 2D systems. Modern advances in fabrication and deposition techniques allow the production of magnetic objects in a deep nanometer regime, i.e. in the order of 1 to 10 nm. However, such a reduction of dimensions towards 1D and 0D structures makes the physics even more complicated, as additional effects such as demagnetisation, dipole interaction and change in magnetic anisotropy start to play a critical role.
The ultimate understanding of these effects and an ability to measure them are the crucial objectives of nanomagnetism - for more details download the NPL Report on the 'Metrological Challenges of Nano-Magnetism' (
PDF 1.53 MB)
Experimental techniques dealing with nanomagnetic properties operate very often with extremely small physical quantities, e.g. moment – of the order of a few Bohr magnetons (μB). Thus, nanomagnetism requires development of novel metrology, satisfying its main objective, i.e. accurate, precise and non-destructive magnetic measurements at the nanoscale.
Magnetic properties of large ensamples of bulk materials, thin films and nanoobjects are studied by a commercial SQUID magnetometer (Quantum Design) which is traceable to standards of the magnetic field and moment.
At NPL our main aim is the development of magnetic sensors, measurement techniques and metrologically and industrially relevant magnetic artefacts for quantitative measurements of the main magnetic parameters and phenomena in nanoscale systems. Methods such as nano-SQUID, nano-Hall sensors, low-temperature Magnetic Force Microscopy and spin polarised Scanning Tunnelling Microscopy are being developed to quantitatively measure the magnetic moment and the magnetic field strength produced by individual magnetic nanostructures.
Our long-term goal is to provide a coherent and accurate set of new measurement standards at the nanoscale as well as underpinning the SI system and the development of measurement methods based on absolute counting of individual spins.
In our research we deal with a large variety of magnetic systems ranging from arrays of nanomagnets (typically 106 to 108 objects) to small ensembles or even individual nanostructures with strongly reduced lateral dimensions (down to a few nm) and small net spin (down to ~103 μB). Both static and resonant magnetic properties have been studied. We constantly develop novel methods of preparation, handling and manipulation of such nanostructures.
These objects are unique metrological artefacts, which may serve as potential magnetic standards at the nanoscale, providing a source of very small and strongly localised magnetic moment, non-homogeneous flux and stray field. They also find applications in IT, magnetic data storage, power generation and biomedical industries.
The development and investigation of these structures allow us to create highly industrially relevant reference samples as well as advance the measurement techniques towards the nanoscale level.
This work is being carried out in collaboration with: