Condensed Matter Physics Research Seminar: Dr Amalio Fernández-Pacheco

Dr Amalio Fernández-Pacheco, of the School of Physics & Astronomy, University of Glasgow, will be presenting a seminar on his research. All are welcome to attend.

Abstract: Three-dimensional nanomagnetism is a new and exciting area of research focused on investigating nanomagnets that extend beyond the standard planar configuration [1]. In these systems, with unconventional geometries and spin interactions, new physical effects emerge, with geometry, topology and chirality becoming interlinked, which paves the way to novel devices with functionalities beyond the substrate plane. Specifically, future non-volatile 3D devices are expected to have ultrahigh storage densities and very high interconnectivity, of great interest for future neuromorphic computing devices [2]. However, the leap to 3D is complex, demanding for new fabrication and characterisation tools [3].

In this seminar, I will focus on two recent results of my group in this area. Firstly, I will show how it is possible to carry out “3D nano-printing” processes in an electron microscope [4, 5], enabling the growth of complex 3D magnetic nanostructures [6]. Exploiting this technique, we have performed pioneering experiments where magnetic information in the form of domain walls can be injected into 3D Permalloy nanowires [7]. To detect this type of process, we have implemented a new type of magneto-optical system exploiting dark-field effects. In the second part, I will show recent results where we have observed the presence of an interlayer Dzyaloshinskii–Moriya interaction (DMI) [8]. This interaction is manifested as a chiral perpendicular exchange bias in synthetic antiferromagnets comprising canted magnetization states [9]. This result, in agreement with recent theoretical [10] and experimental [11] works, opens a new route to create 3D spin textures in multi-layered magnetic systems.

I acknowledge funding from EPSRC (grants: EP/M008517/1 and EP/L015978/1), from the Cambridge Winton Program for the Physics of Sustainability, the Royal Society ( grant: KFZA/318) and EU funding via the COST action CELINA.

[1] Fernández-Pacheco et al, Nature Comm. 8, 15756 (2017). [2] Torrejón et al, Nature 547, 428 (2017). [3] Donnelly et al, Nature 547, 328 (2017). [4] Sanz-Hernández et al, Beilstein J. Nanotechnol. 8, 2151 (2017). [5] Fowlkes et al, ACS Appl. Nano Mater. 1, 1028 (2018). [6] Sanz-Hernández et al, Nanomaterials 8, 483 (2018). [7] Sanz-Hernández et al, ACS Nano 11, 11066 (2017). [8] Fernández-Pacheco et al, arXiv:1810.01801 (2018). [9] Ummelen et al, Appl. Phys. Lett. 110, (2017). [10] Vedmendenko et al, arXiv:1803.10570v2 (2018). [11] Han et al, arXiv:1809.01080v1 (2018).

For further information, please contact Dr Satoshi Sasaki.