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

authors	Marcano, N; Algarabel, PA; Barquin, LF; Araujo, JP; Pereira, AM; Belo, JH; Magen, C; Morellon, L; Ibarra, MR
nationality	International
journal	PHYSICAL REVIEW B
keywords	NONLINEAR AC SUSCEPTIBILITY; SPIN-GLASSES; TRANSITION; BEHAVIOR
abstract	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.
publisher	AMER PHYSICAL SOC
issn	2469-9950
isbn	2469-9969
year published	2019
volume	99
issue	5
digital object identifier (doi)	10.1103/PhysRevB.99.054419
web of science category	Materials Science, Multidisciplinary; Physics, Applied; Physics, Condensed Matter
subject category	Materials Science; Physics
unique article identifier	WOS:000459221500008