2023 Provost’s Program Black and Indigenous Postdoctoral Scholar: Shoronia Cross (he/him)

The prospect of designing novel data storage technologies based on nanomaterials, whose electric polarization and magnetization can be controlled simultaneously, promises to yield higher storage densities and faster processing speeds, while simultaneously reducing the power requirements of these devices. The class of materials known as multiferroics are ideal candidates in that regard, as they are simultaneously ferroelectric and ferromagnetic. The overall objective of this research is to quantitatively describe the correlation between the degrees of freedom of ferroelectric nanocrystals (NCs) with respect to their crystal and electronic structure, at the nanoscale and ensemble level, when interfaced with ferromagnetic NCs, in multiferroic nanocomposites.

The proposed project aligns perfectly with Waterloo’s strategic research theme of Advancing Research for Global Impact. With applications to several of the important global challenges outlined in Waterloo’s strategic research plan, including quantum information, artificial intelligence, and nanotechnology, our projects will help to bolster Waterloo’s national and global position within these key research fields. Our innovative approach to the development and characterization of magnetoelectric nanomaterials has tremendous implications for the advancement of key research fields, which in turn, will drive the advancement of our society. No single field can tackle the obstacles of the increasingly complex, real-world problems our society faces, but through international collaborations across diverse backgrounds, we hope to open myriad new perspectives on these problems, which is the key to ultimately solving them.

• To gain a more in-depth fundamental understanding of magnetic materials, and more practical, hands-on training in magnetic and magneto-optical materials characterization techniques.
• To gain some teaching experience for at least one term.
• To focus my area of interest within the field of magnetic nanomaterials, and to become a more independent researcher within that area.

I was the recipient of the Vanier Canada Graduate Scholarship during my Ph.D. studies, which gave me the freedom to focus entirely on my research, and not have to worry about finances or TA responsibilities.

We will explore nanocrystalline film composites of alternating layers of ferromagnetic cobalt ferrite (CFO) nanocrystals (NCs) and ferroelectric barium titanate (BTO) NCs, as well as CFO NCs encapsulated within hollow BTO nanostructures. In conjunction with the investigation of BTO nanocomposites, we will further investigate the effects of composite architecture by using lead titanate (PTO) nanowires (NWs) as a strongly ferroelectric component upon which we can nucleate and grow CFO NCs directly.

In addition, we will investigate the magnetoelectric properties of dilute semiconductor (DMS) NCs prepared by doping small concentrations of Mn2+ ions into cesium-lead-halide (Cl, Br, I) perovskites. We hypothesize that the ability to modulate NC electronic structure by tailoring halide composition will effectively allow for fine tuning the conduction band spin-splitting by altering the exchange interactions between conduction band states and the paramagnetic dopant centers. We will simultaneously explore the possibility of doping these NCs with other paramagnetic transition metal dopants (i.e., Co2+, Cr3+, Ni2+) to elucidate the effect of the dopants’ electronic structure on their coupling with the NC lattice, and achieve another level of control of the spin states. The ultimate goal is to achieve spin polarization and establish perovskite-based DMSs as a new class of spintronics materials.

These complimentary projects allow for the intrinsic (through doping) and extrinsic (through nanocomposites) control of the magneto-electric properties of perovskite-based nanomaterials, which will allow for a more fundamentals - and applications-based understanding of these materials, respectively.

The University of Waterloo has a world-renowned reputation as a leader in the fields of science and technology, as well as tremendous collaborations between industry and academia, which can facilitate the advancement of science. The research being conducted by the Radovanovic group is at the forefront of the fields of magnetic nanomaterials and magneto-plasmonics. Furthermore, the Radovanovic group is one of the few groups in the world with a magnetic circular dichroism (MCD) spectrometer capable of performing variable temperature magneto-optical measurements at fields of up to 7 Tesla, which is a powerful tool for the characterization of magnetic materials.

What I currently enjoy about the University of Waterloo is that it is a university that favours interdisciplinary research collaboration and values principles such as diversity, inclusion, equality, respect, and excellence in research and innovation.

In my spare time, I enjoy brewing my own beer, playing guitar, and working on my car.