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Electron spin resonance and quantum critical phenomena in VO x multiwall nanotubes
Author(s) -
Demishev S. V.,
Chernobrovkin A. L.,
Goodilin E. A.,
Glushkov V. V.,
Grigorieva A. V.,
Samarin N. A.,
Sluchanko N. E.,
Semeno A. V.,
Tretyakov Yu. D.
Publication year - 2008
Publication title -
physica status solidi (rrl) – rapid research letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.786
H-Index - 68
eISSN - 1862-6270
pISSN - 1862-6254
DOI - 10.1002/pssr.200802108
Subject(s) - condensed matter physics , antiferromagnetism , spins , spin (aerodynamics) , electron paramagnetic resonance , ground state , atmospheric temperature range , electron , resonance (particle physics) , quantum , exponent , critical exponent , phase (matter) , physics , materials science , phase transition , nuclear magnetic resonance , atomic physics , quantum mechanics , thermodynamics , linguistics , philosophy
Basing on the high frequency (60 GHz) electron spin resonance study of the VO x multiwall nanotubes (VO x ‐NTs) carried out in the temperature range 4.2–200 K we report: (i) the first direct experimental evidence of the presence of the antiferromagnetic dimers in VO x ‐NTs and (ii) the observation of an anomalous low temperature growth of the magnetic susceptibility for quasi‐free spins, which obey the power law χ ( T )∼1/ T α with the exponent α ≈ 0.6 in a wide temperature range 4.2–50 K. We argue that the observed departures from the Curie–Weiss behaviour manifest the onset of the quantum critical regime and formation of the Griffiths phase as a magnetic ground state of these spin species. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)