Project description
The tale of two 'powers' may be rewritten to reflect their interdependence
Hybrid materials composed of two or more separate ones at the nanometre or molecular level present both opportunities and challenges related to their interactions. Emergent and exciting new properties can be harnessed for research and applications. However, understanding their interactions in order to control them can be tricky. Ferromagnet–superconductor hybrids have been the topic of intensive research over the last couple of decades. They include intriguing combinations such as coupled ferromagnetic and superconducting films and magnetic nanowires in superconducting matrices. Most of the research has focussed on the effects of the ferromagnet on the superconductor, assuming the latter does not affect the former. The EU-funded SUPER-MAGNONICS project is building on recent theoretical and experimental evidence that this is not the case, with a goal of shedding light on some of the interesting ways in which superconductivity and magnetisation are coupled bi-directionally.
Objective
The proposal addresses a problem that has received very little experimental attention despite its fundamental and technological interest: the coupling between superconducting state and magnetization dynamics in artificial superconductor (S) / ferromagnet (F) hybrid structures. Most of the studies consider that the superconductor is very strongly affected by the interaction with a ferromagnet which, on the contrary, is in a static, equilibrium state and whose order parameter (the magnetization) remains unaffected. However, theoretical studies and a few recent experiments have shown that superconductivity can strongly affect ferromagnetism in various ways. This is the case for instance if one considers low-energy excitations of the magnetization (e.g. magnons), or if one looks at the relaxation from dynamic non-equilibrium states, e.g. the decay of the precession of the macroscopic magnetic moment.
In this regard, the proposal has two central objectives, which correspond to two mechanisms of coupling between superconductivity and magnetization dynamics, respectively of electromagnetic and electronic nature. The former objective is concerned with the experimental demonstration of electrical magnon excitation and detection in superconductor/ferromagnet hybrids, that will be applied to the design of dynamic magnonic crystals. Superconductors with different penetrations lengths and intrinsic flux pinning as well as various ferromagnets will be combined. The latter objective involves the understanding of spin pumping and spin diffusion effects in superconductors through ferromagnetic resonance and electrical detection. Special attention will be paid to the used of Yttrium Iron Garnet in insulating ferromagnet/superconductor interfaces, as it presents low intrinsic damping even in thin films. Further combinations with s-wave and d-wave superconductors as well as half-metal ferromagnets will also be explored in this context.
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Programme(s)
Funding Scheme
MSCA-IF - Marie Skłodowska-Curie Individual Fellowships (IF)Coordinator
75794 Paris
France