Magnetic Imaging at Low dimensions & high Frequencies – MILF

Despite the intensive research upon magnetism and magnetic materials, several phenomena remain unclear. For example, experimental results enabling to access a domain wall inner structure during its displacement are still missing. The well-known Walker breakdown, where a change of domain wall structure from Transverse to Vortex associated to its motion needs to be experimentally proven. Such need is also true for the vibrational behavior of micromagnetic objects as vortex precession or domain walls deformation prior to unpinning, and is also emerging for skyrmions phase dynamic. This characterization is mandatory for the potential use of these magnetic objects in recording or logic media. Therefore there is actually a need as well as intense efforts in magnetic imaging (MI) spatially resolved with high sensitivity and frequency time scale. The MILF project aims at offering at the same time high frequency and high spatial resolution by : (i) developing a fully electro(magneto)static time-resolved stroboscopic magnetic imaging TEM technique that could be used on a broad range of commercial TEM’s ; (ii) proposing an exhaustive experimental comparison of such instrument capacities versus existing MI techniques along with their respective temporal and spatial resolutions as well as their sensitivity in magnetic signal. These two objectives will be achieved by the design of model samples taking place in dedicated chipsets that will carry, in a single device, the sample and its pumping design. The MILF project is entering a very intense field of research with the main advantage of presenting among the best spatial resolution. It proposes not to reach the best temporal resolution among other MI or TEM techniques but to explore a less explored part of magnetism dynamics trough real space where findings should be of fundamental interest. It will require inputs from other MI techniques and provide new complementary ones generating a fruitful networking activity. Due to the technological level of temporal studies and especially in pump-probe design and magnetic sensitivity, MILF aims at being very active in the French magnetism community.
This experimental project is relying on an original combination of well-known technologies mastered in the consortium, namely electron optics, lab on chip and high frequency electronics, to promote fundamental knowledge of micromagnetism dynamic. Achieving this will be possible by a precise work between an academic leader and its strong relationship with the related industry (electron microscope manufacturers and microwave companies). The know how that is actually existing in the academic network of the coordinator will be a real benefit for fruitful discussions towards the industry in charge of needed instruments. Such an approach will renew the standards that usually consist of selecting an item from a catalog to roughly fits needs instead of designing an original one accordingly. This is one of the strength of such experimental project as it relies on a crossover knowledge of wanted specificities (such as waveform design or electro-magnetic blanking systems) bringing a perfect mixing in between established companies and new design emerging from an already installed academic partner. It will eventually bridge a future common device that could be of great interest for worldwide labs. It worth noticing that every part of the proposed project, from the sample holder system coupled to the stimuli pump – that is already overcoming the complexity of accessing more that one microwave signal within the electron column – to the fully electric time-resolved system, could lead to appraising of academic research towards manufacturers.