Dresden 2020 – scientific programme
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MA: Fachverband Magnetismus
MA 49: Focus Session: Higher-Order Magnetic Interactions – Implications in 2D and 3D Magnetism II
MA 49.5: Talk
Thursday, March 19, 2020, 16:15–16:30, HSZ 04
Competing Non-collinear Magnetic Phases in Osmates Double Perovskites — •Dario Fiore Mosca — University of Vienna & VDSP, Vienna, Austria
The interplay between electron correlation, local symmetry and spin-orbit coupling is among the most challenging aspect of condensed matter physics. These energy scales are simultaneously active in 5d transition metal oxides, which represent a rich playground for discovering new quantum states of matter. In particular, strong relativistic effects can lead to the formation of complex non-collinear magnetic orderings, whose origin cannot be understood within a standard Heisenberg picture. In our work, we study the ground state of the 5d1 osmate-based double perovskite Ba2NaOsO6 and decipher the driving mechanism that leads to the onset of the observed canted antiferromagntic pattern. The structural, electronic and magnetic properties of Ba2NaOsO6 are computed using fully relativistic and magnetically constrained DFT + U. We find that the magnetic energy landscape (in particular the canting angle) depends critically on the cooperative Jahn-Teller distortions and on the strength of the effective electron correlation U-J. In order to acquire additional information on the quantum origin of the canted AFM state we map the first principles total energies onto an extended pseudospin Hamiltonian, and find that dipolar and octupolar terms are the key interactions that drive the stabilization of the noncollinear ground state.