Spin-Orbit Interaction and Jahn-Teller Transition in Bimetallic Oxalates

Journal Article · Thu Jan 01 00:00:00 EST 2009 · Polyhedron

DOI:https://doi.org/10.1016/j.poly.2008.11.007· OSTI ID:967103

Fishman, Randy Scott ^[1]; Okamoto, Satoshi ^[1]; Reboredo, Fernando A ^[1]

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1. ORNL

The C3-symmetric crystal-field potential in the Fe(II)Fe(III) bimetallic oxalates splits the L = 2 Fe(II) multiplet into two doublets and one singlet. In compounds that exhibit magnetic compensation, one of the doublets lies lowest in energy and carries an average orbital angular momentum Lcf z that exceeds a threshold value of roughly 0.25. In a range of Lcf z , a Jahn-Teller (JT) distortion increases the energy splitting of the low-lying doublet and breaks the C3 symmetry of the bimetallic planes around the ferrimagnetic transition temperature. Due to the competition with the spin-orbit coupling, the JT distortion disappears at low temperatures in compounds that display magnetic compensation. A comparison with recent measurements provides strong evidence for this inverse, low-temperature JT transition. The size of the JT distortion is estimated using first-principles calculations, which suggest that the long-range ordering of smaller, non-C3-symmetric organic cations can eliminate magnetic compensation. Keywords: Jahn-Teller distortion; Spin-orbit interaction; Crystal fields; Bimetallic oxalates

• Research Organization: Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States)
• Sponsoring Organization: USDOE Office of Science (SC)
• DOE Contract Number: DE-AC05-00OR22725
• OSTI ID: 967103
• Journal Information: Polyhedron, Vol. 28, Issue 9-10; ISSN 0277-5387
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
CRYSTAL FIELD
L-S COUPLING
MULTIPLETS
ORBITAL ANGULAR MOMENTUM
OXALATES
IRON COMPOUNDS
BIMETALS
JAHN-TELLER EFFECT