Exotic magnetism on the quasi-FCC lattices of the d3 double perovskites La2NaB'O6 (B' = Ru, Os)
- ORNL
- ISIS Facility, Rutherford Appleton Laboratory (ISIS)
- University of South Carolina
- University of South Carolina, Columbia
We find evidence for long-range and short-range ($$\zeta$$~$$=$$~70~\AA~at 4~K) incommensurate magnetic order on the quasi-face-centered-cubic (FCC) lattices of the monoclinic double perovskites La$$_2$NaRuO$$_6$$ and La$$_2$$NaOsO$$_6$$ respectively. Incommensurate magnetic order on the FCC lattice has not been predicted by mean field theory, but may arise via a delicate balance of inequivalent nearest neighbour and next nearest neighbour exchange interactions. In the Ru system with long-range order, inelastic neutron scattering also reveals a spin gap $$\Delta$$~$$\sim$$~2.75~meV. Magnetic anisotropy is generally minimized in the more familiar octahedrally-coordinated $3d^3$ systems, so the large gap observed for La$$_2$$NaRuO$$_6$$ may result from the significantly enhanced value of spin-orbit coupling in this $4d^3$ material.
- Research Organization:
- Energy Frontier Research Centers (EFRC) (United States). Heterogeneous Functional Materials Center (HeteroFoaM); Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States). High Flux Isotope Reactor (HFIR)
- Sponsoring Organization:
- USDOE Office of Science (SC)
- DOE Contract Number:
- DE-AC05-00OR22725
- OSTI ID:
- 1136802
- Journal Information:
- Physical Review Letters, Vol. 112, Issue 11; ISSN 0031--9007
- Country of Publication:
- United States
- Language:
- English
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