Exotic magnetism on the quasi-FCC lattices of the d3 double perovskites La2NaB'O6 (B' = Ru, Os)

Journal Article · Wed Jan 01 00:00:00 EST 2014 · Physical Review Letters

DOI:https://doi.org/10.1103/PhysRevLett.112.117603· OSTI ID:1136802

Aczel, Adam A ^[1]; Baker, Peter J. ^[2]; Bugaris, Dan ^[3]; Yeon, Jeongho ^[4]; Zur Loye, Hans-Conrad ^[3]; Guidi, T. ^[2]; Adroja, D. T. ^[2]

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1. ORNL
2. ISIS Facility, Rutherford Appleton Laboratory (ISIS)
3. University of South Carolina
4. 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

Related Subjects

4d and 5d magnetism
spin-orbit coupling