Evolution of magnetic states in frustrated diamond lattice antiferromagnetic Co(Al1-xCox)(2)O-4 spinels

O. Zaharko, A. Cervellino, V. Tsurkan, Niels Bech Christensen, A Loidl

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    Abstract

    Using neutron powder diffraction and Monte Carlo simulations we show that a spin-liquid regime emerges at all compositions in the diamond-lattice antiferromagnets Co(Al1−xCox)2O4. This spin-liquid regime induced by frustration due to the second-neighbor exchange coupling J2 is gradually superseded by antiferromagnetic collinear long-range order (k=0) at low temperatures. Upon substitution of Al3+ by Co3+ in the octahedral B site the temperature range occupied by the spin-liquid regime narrows and TN increases. To explain the experimental observations we considered magnetic anisotropy D or third-neighbor exchange coupling J3 as degeneracy-breaking perturbations. We conclude that Co(Al1−xCox)2O4 is below the theoretical critical point J2/J1=1/8, and that magnetic anisotropy assists in selecting a collinear long-range ordered ground state, which becomes more stable with increasing x due to a higher efficiency of O-Co3+-O as an interaction path compared to O-Al3+-O. © 2010 The American Physical Society
    Original languageEnglish
    JournalPhysical Review B Condensed Matter
    Volume81
    Issue number6
    Pages (from-to)064416
    ISSN0163-1829
    DOIs
    Publication statusPublished - 2010

    Bibliographical note

    Copyright 2010 American Physical Society

    Keywords

    • Materials and energy storage
    • Superconducting materials

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