Frustration by competing interactions in the highly-distorted double perovskites La2NaB'O6 (B' = Ru, Os)

Journal Article · Tue Jan 01 00:00:00 EST 2013 · Physical Review. B, Condensed Matter and Materials Physics

DOI:https://doi.org/10.1103/PhysRevB.87.014435· OSTI ID:1076890

Aczel, Adam A ^[1]; Bugaris, Dan ^[2]; Li, Ling ^[3]; Yan, Jiaqiang ^[1]; Dela Cruz, Clarina R ^[1]; Zur Loye, Hans-Conrad ^[2]; Nagler, Stephen E ^[1]

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1. ORNL
2. University of South Carolina
3. University of Tennessee, Knoxville (UTK)

The usual classical behaviour of S = 3/2, B-site ordered double perovskites generally results in simple, commensurate magnetic ground states. In contrast, heat capacity and neutron powder diffraction measurements for the S = 3/2 systems La2NaB'O6 (B = Ru, Os) reveal an incommensurate magnetic ground state for La2NaRuO6 and a drastically suppressed ordered moment for La2NaOsO6. This behaviour is attributed to the large monoclinic structural distortions of these double perovskites. The distortions have the effect of weakening the nearest neighbour superexchange interactions, presumably to an energy scale that is comparable to the next nearest neighbour superexchange. The exotic ground states in these materials can then arise from a competition between these two types of antiferromagnetic interactions, providing a novel mechanism for achieving frustration in the double perovskite family.

• Research Organization: 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: 1076890
• Journal Information: Physical Review. B, Condensed Matter and Materials Physics, Vol. 87, Issue 1; ISSN 1098-0121
• Publisher: American Physical Society (APS)
• Country of Publication: United States
• Language: English

Related Subjects

double perovskites
magnetism