PhD on topological insulators/magnetic systems for spin-charge conversion
Partners involved: UMPhy (lead), C2N, SOLEIL
Diana SHE has started her PhD in October 2020.
Her main objective will be to study spin to charge current conversion from a BiSb topological insulator. In particular she will optimize growth conditions of BiSb by molecular beam epitaxy(MBE) topped with ferromagnetic half-metals (MnBi, MnSb). The latter are 100% spin polarized at Fermi level and may reduce the current shunting as well. Moreover, she will focus on characterizing topological surface states by ARPES (Angle Resolved PhotoEmision Spectroscopy). And finally she will perform spin transport measurements in order to qualify spin-charge conversion in BiSb.
PhD on static and dynamic properties of skyrmions in ferrimagnetic systems
Partners involved: LPS (lead), UMPhy, SOLEIL
Sujit kumar PANIGRAPHY has started in November 2020.
Thesis Abstract: ” Magnetic skyrmions, nanobubbles with a fixed chirality, are topological magnetic textures in a sense that no continuous path exists to collapse them toward the uniform ferromagnetic state. While many groups are now able to stabilize them and control their motion with electrical current in ferromagnetic layers, experiments are facing some limits (skyrmions size, limited velocities due to pinning, gyrotropic deflection due to topology). These problems could be overcome using antiferromagnetic situations (e.g. synthetic antiferromagnets, antiferromagnetic samples, or ferrimagnetic samples). In those, the zero magnetization should enable much smaller skyrmions, and the exaltation of magnetization dynamics should increase the skyrmion velocity and cancel the gyrotropic deflexion. The purpose of the Ph.D. is, based on our experience on ferromagnetic skyrmions, to implement skyrmions in such materials and probe their dynamics.”
PhD on ultrafast spintronic
Partners involved: SPEC (lead), UMPhy, SOLEIL
Sanjay RENE has started his PhD in October 2021.
He will explore the transport of spincurrent in different systems and particularly through antiferromagnetic (AF) insulating layers. In fact, because pure spin currents can now be generated, propagated and detected on sub-picosecond timescales and at nano-sizes, one can therefore envision the possibility of ultrafast spintronic components and the emergence of terahertz spintronic devices.
On the other hand, AF materials, which present interesting terahertz dynamical properties are currently attracting a substantial renew of interest as it is now well established that spin currents can efficiently interact with them. In particular, magnonic spin currents can be transported through insulating AF materials. While this has been clearly evidenced in the DC and GHz regime, opened questions remain regarding AF spin current transport properties at picosecond timescales, i.e. when spin currents coherently match specific antiferromagnetic THz resonances. The objectives of his PhD are therefore to tackle this issue by carrying out time-resolved magneto-optical experiments in well-designed systems including AF insulators.
PhD on Confined propagating spin-waves for data processing
Partners involved: C2N (lead), UMPhy
Sali Salama has started in December 2021.
Thesis abstract: Spin-waves, the collective excitations of magnetic moments about an equilibrium background configuration, do not generate Joule heating, can be easily controlled in their environment and can present strong non-linearities and non-reciprocities. These properties triggered extended experimental investigations to use the spin-waves as a way to store, transport and process information. The PhD. Program of Mrs Sali Salama will specifically address confined spin-waves in magnonic nanostructures and their relevance for Boolean and non-Boolean applications. This experimental work will be based on the IMAGeSPIN funded microfocused Brillouin Light Scattering equipment which uniquely allows to spatially map spin-waves combining frequency, time and phase resolution.