Cluster-glass dynamics of the Griffiths phase in Tb5-xLaxSi2Ge2

Article

关键词: NONLINEAR AC SUSCEPTIBILITY;    SPIN-GLASSES;    TRANSITION;    BEHAVIOR;   

DOI  :  10.1103/PhysRevB.99.054419

来源: SCIE

【 摘 要 】

The static magnetization and dynamic susceptibility responses of the cluster system within a Griffiths phase of the magnetocaloric compound Tb5-xLaxSi2Ge2 (x = 0.075) have been investigated. A novel cluster-glass state within the Griffiths phase is formed at a characteristic freezing temperature where short-range ferromagnetic correlations set in the paramagnetic regime. Ferromagneticlike correlations are built up at around 155 K, which suddenly become frozen at a lower temperature similar to 140 K, thus in analogy with a reentrant spin glass behavior. The ac susceptibility near the freezing temperature follows a critical slowing down process characterized by tau(0) = 10(-13)s and dynamic exponents zv similar to 6 and beta similar to 0.4, similar to well-known spin glass systems. The nonlinear ac susceptibility analysis shows clearly the existence of a transition associated to the reentrant behavior. The origin of the intermediate cluster-glass phase inside the Griffiths phase is proposed to be the result of a combination of short-ranged RKKY intralayer positive exchange interactions between rare-earth Tb3+ ions and antiferromagnetic exchange between adjacent interlayers involving Si and Ge atoms in connection to the Tb(3+)atoms.

【 授权许可】

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