Orbital ordering transition in probed with Mössbauer spectroscopy

Heary, Ryan; Coffey, D.; Marco, Michael De; Khalifah, Peter G.; Toorongian, Steven A.; Haka, Michael S.

doi:10.1016/j.physb.2006.12.072

Cited by 3 publications

(1 citation statement)

References 6 publications

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“…However, these bond distances are also compatible with an S ≈ 0 at each Ru 4+ site (dxz ↑↓ ,dxy ↑↓ ,dyz 0 ), as originally proposed by Khalifah et al; 6 to distinguish between these scenarios is a difficult task. 7 At high temperature, T > T S , the undistorted Ru-O octahedra observed by neutron diffraction have been assigned to an equal orbital occupation that quenches the orbital degrees of freedom. But these equal bond lengths could also be a consequence of a rapid fluctuation in the orbital occupancy, which does not quench the orbital channel but results in an average Ru-O bond.…”

Section: Introductionmentioning

confidence: 99%

Rapidly fluctuating orbital occupancy above the orbital ordering transition in spin-gap compounds

et al. 2011

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Several spin systems with low dimensionality develop a spin-dimer phase within a molecular orbital below T S , competing with long-range antiferromagnetic order. Very often, preferential orbital occupancy and ordering are the actual driving force for dimerization, as in the so-called orbitally driven spin-Peierls compounds (MgTi 2 O 4 , CuIr 2 S 4 , La 4 Ru 2 O 10 , NaTiSi 2 O 6 , etc.). Through a microscopic analysis of the thermal conductivity κ(T) in La 4 Ru 2 O 10 , we show that the orbital occupancy fluctuates rapidly above T S , resulting in an orbital-liquid state. The strong orbital-lattice coupling introduces dynamic bond-length fluctuations that scatter the phonons to produce a κ (T) ∼ T (i.e., glasslike) above T S . This phonon-glass to phonon-crystal transition is shown to occur in other spin-dimer systems, like NaTiSi 2 O 6 , pointing to a general phenomenon.

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Section: Introductionmentioning

confidence: 99%

Rapidly fluctuating orbital occupancy above the orbital ordering transition in spin-gap compounds

et al. 2011

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Mössbauer-Active Transition Metals Other than Iron

Gütlich

Bill²,

Trautwein

2010

Mössbauer Spectroscopy and Transition Metal Chemistry

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Magnetic properties ofRuSr2GdCu2O8using the temperature dependence of the Mössbauer spectrum

et al. 2008

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Mössbauer spectra were measured from 4.2 to 145 K on a 99 Ru enriched sample of RuSr 2 GdCu 2 O 8 which magnetically orders at 138 K and has a full transition to superconductivity at 8.7 K with an onset at ϳ13 K. The superconducting transition has no effect on the spectrum which is determined by the hyperfine magnetic field due to the magnetic order. At low temperatures there is a rapid decrease of this hyperfine magnetic field with increasing temperature indicating a gapless or a very low energy magnon spectrum. We use a localmoment model which includes coupling between nearest-neighbor in-plane Ru moments and between the Ru and Gd moments which are separated by a superconducting CuO layer and a SrO layer to calculate the magnon spectrum and use this to estimate the strength of the exchange interactions based on the hyperfine magneticfield temperature dependence. The coupling strength is ϳ275 K for Ru-Ru coupling and ϳ30 K for Ru-Gd coupling.

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Orbital ordering transition in probed with Mössbauer spectroscopy

Cited by 3 publications

References 6 publications

Rapidly fluctuating orbital occupancy above the orbital ordering transition in spin-gap compounds

Rapidly fluctuating orbital occupancy above the orbital ordering transition in spin-gap compounds

Mössbauer-Active Transition Metals Other than Iron

Magnetic properties ofRuSr2GdCu2O8using the temperature dependence of the Mössbauer spectrum

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