CCQ Seminar: Danis Badrtdinov

Tuesday Sep 8, 2020, 12:00 PM → 1:00 PM America/New_York

Insights into the complex magnetic orders of rare-earth nickelates  

 Rare-earth nickelate systems have received significant attention in recent years,  due to their rich phase diagram containing a combined structural and metal-insulator  transition, and additionally the formation of long-range magnetic order, which both  can be tuned via the ionic size of rate-earth element. While the mechanism of the  combined structural and metal-insulator transition is well studied, the nature of  magnetic order is still under debate. Different experimental methods such as neutron  diffraction and resonant X-ray scattering predict a complex magnetic order, which is  predicted to be collinear or non-collinear, respectively. Within this talk I will present  our recent theoretical results, which shed light on the nature of the complex magnetic  ordering in rare-earth nickelate systems. Using density functional theory methods  combined with Wannier function techniques, microscopic magnetic models were  constructed, containing all relevant exchange interactions. Obtained models clearly  explain the formation of experimentally observed antiferromagnetic order in the  systems, while the inclusion of spin-orbit coupling effects demonstrates that the  magnetic anisotropy is very small. Our results provide a clear picture of the trends of  the magnetic order across the nickelate series, and give insights into the coupling  between magnetic order and structural distortions.