EPSRC DTP PhD studentship: Magnetic materials with ultralow damping for magnonic metamaterials and devices

Energy efficiency within technology is a key challenge in achieving a greener world and is a major factor in determining the performance and market attractiveness of a device. The memory capability inherent in magnetism, which can be tailored within multilayered magnetic film, promises huge energy savings within non-volatile devices. This vision has underpinned the growth of research in spintronics and magnonics, where the general aim is to exploit spin currents and spin waves, respectively. The main obstacle is the energy dissipation in high frequency magnetic processes, also referred to as “magnetic damping”. In particular, damping within the most frequently used metallic materials limits the propagation length of the spin wave carrier signal in magnonic devices [1] and the power emitted by spin-transfer torque microwave oscillators [2].

Within this project, we will explore fabrication of magnonic and spintronic metamaterials and devices from CoFe alloys, which have very recently been shown to have damping that is an order of magnitude smaller than in the best alternative magnetic metallic alloys [3]. The performance of the fabricated materials will be tested using microwave and timeresolved magneto-optical experiments and modelled using micromagnetic simulations. Finally, we will integrate the best of the developed materials within magnonic metamaterials and high-frequency spintronic devices for spin-wave based data and electromagnetic signal processing.

1. C. S. Davies, A. Francis, A. V. Sadovnikov, S. V. Chertopalov, M. T. Bryan, S. V. Grishin, D. A. Allwood, Y. P. Sharaevskii, S. A. Nikitov, and V. V. Kruglyak, “Towards graded-index magnonics: Steering spin waves in magnonic networks”, Phys. Rev. B 92, 020408 (2015).

2. P. S. Keatley, S. R. Sani, G. Hrkac, S. M. Mohseni, P. Durrenfeld, T. H. J. Loughran, J. Åkerman, and R. J. Hicken, “Direct observation of vortex dynamics generated by nanocontact spin-torque vortex oscillators”, Phys. Rev. B 94, 060402(R) (2016).

3. M. A.W. Schoen, D. Thonig, M. L. Schneider, T. J. Silva, H. T. Nembach, O. Eriksson, O. Karis, and J. M. Shaw, “Ultra-low magnetic damping of a metallic ferromagnet”, Nature Physics 12, 839 (2016).