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Article Dans Une Revue Physical Review B: Condensed Matter and Materials Physics (1998-2015) Année : 2015

Random dilution effects in the frustrated spin chain β − CaCr 2 − x Sc x O 4

Résumé

Random dilution effects in the magnetic zigzag ladder (J1−J2 chain) β−CaCr2−xScxO4 have been investigated combining magnetic susceptibility, specific heat measurements, and neutron scattering. The pseudogapped magnetic excitations observed above TN in β−CaCr2O4 (x=0) persist up to x=0.3 with an increasing characteristic frequency E0 but vanish for x=0.5 for which a quasielastic signal extending up to 8meV becomes the characteristic feature of the magnetic spectrum. Magnetic ordering is seen up to x=0.3 with decreased ordering temperature TN and correlation length. The results are interpreted in terms of the progressive confinement of one-dimensional excitations within shorter chains as x increases and emphasize the crucial role of J2 in propagating magnetic excitations. For an average chain length l smaller than ∼16 magnetic atoms, the system breaks apart into a set of disconnected units with the dynamical properties of a spin glass.
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hal-02161227 , version 1 (20-06-2019)

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M. Songvilay, S. Petit, V. Hardy, J. Castellan, G. André, et al.. Random dilution effects in the frustrated spin chain β − CaCr 2 − x Sc x O 4. Physical Review B: Condensed Matter and Materials Physics (1998-2015), 2015, 91 (5), pp.054408. ⟨10.1103/PhysRevB.91.054408⟩. ⟨hal-02161227⟩
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