Host: Paris Sud University
Location: Palaiseau, France
Supervisor: Liza Herrera Diez
Scientific project:
This project will explore E-field gating of magnetic domain wall motion using parallel arrays of bipolar and non-volatile gates defined by light-controlled ionics. Photo-active polymer films will be the support of mobile ionic charges which under a gate voltage can migrate to the surfaces of the polymer. Photo-induced polymerisation will then fix the position of the ionic charges creating non-volatile gates. By appropriately choosing the light exposure pattern and/or the gate contact geometry, arrays of non-volatile gates will be created across extended areas with both positive and negative charges. The flexible polymer containing the gate design can be later easily placed on top of a magnetic film to apply strong E-fields in a unique ‘stick-on’ device concept that can be transferred and reused on multiple magnetic surfaces. This device design is inspired on energy harvesting technologies and this project will innovate in adapting it to spintronics devices.
This approach will allow for creating gate arrays with accumulation of charges of both polarities and different charge densities without the need of wiring or applied voltages. Simply sticking the polymer containing the gate array on a magnetic material with perpendicular anisotropy will directly transfer a multistate anisotropy landscape onto the film. This will be exploited to study in detail the motion of magnetic domain walls in a multilevel artificial pinning potential. A key aspect of the project will be creating gate arrays that can effectively define DW paths and nucleation/pinning points with the ultimate goal of designing domain wall based ‘stick-on’ logic circuits.