Muon spin relaxation in spin-peierls phase of NaV2O5

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Date
2004-02-04
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Australian Institute of Physics
Abstract
Ground states of one-dimensional antiferromagnets are topical subjects in regard of their quantum mechanical nature. Spin-Peierls (sP) systems and even-legged ladders systems, have a fundamental non magnetic state which is a singlet. It is separated by a gap, from the triplet magnetic excitations. The sP transition occurs at low temperature (TsP), in several quasi-onedimensional antiferromagnetic compounds which do not undergo a transition to long range magnetic order. Coupling with phonons leads to a crystalline distortion and the chain dimerises. CuGeO3 (TsP = 14.2 K) [1] is the first inorganic sP compound to have been discovered, NaV2O5 which is the subject of the present study, does not appear to be a conventional sP system. The sP transition is accompanied here, by charge ordering, in the sense that above TsP, one electron is orbiting around a V4+ - O2- - V4+ group, then settling on one specific vanadium ion below TsP. Depolarisation of muons have been carried out on NaV2O5, between 6 and 150 K, through the transition at TsP = 33 K. Surprisingly the transition is well fitted throughout to a stretched exponential, exp−[λ (T ).t]β (T ) . While λ rises dramatically below TsP, the exponent β is greater than 1 above TsP but falls to below 1/3 at 6 K as is the case in frustrated systems?
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Keywords
Muon spin relaxation, Antiferromagnetism, Quantum mechanics, Temperature range 0065-0273 K, Phonons, Chain reactions, Orbits, Depolarization
Citation
Aïn, M., Lord, J., Jegoudez, J., & Revcolevschi. A. (2004). Muon spin relaxation in spin-peierls phase of NaV2O5. Poster presented to the 28th Annual Condensed Matter and Materials Meeting, Charles Sturt University, Wagga Wagga, 3-6 February 2004. Retrieved from: https://www.physics.org.au/wp-content/uploads/cmm/2004/04handbook.pdf