title: Absence of magnetic order in Yb3Ga5O12: relation between phase transition and entropy in geometrically frustrated materials.
abstract: From muon spin relaxation spectroscopy experiments, we show that the sharp peak (lambda-type anomaly) detected by specific heat measurements at 54 mK for the ytterbium gallium garnet compound, Yb3Ga5O12, does not correspond to the onset of a magnetic phase transition, but to a pronounced building up of dynamical magnetic pair correlations. Beside the lambda anomaly, a broad hump is observed at higher temperature in the specific heat of this garnet and other geometrically frustrated compounds. Comparing with other frustrated magnetic systems we infer that a ground state with long-range order is reached only when at least 1/4-1/3 of the magnetic entropy is released at the lambda transition.
authors: Commissariat à l'Energie Atomique, Département de Recherche Fondamentale sur la Matière Condensée, F-38054 Grenoble Cedex 9, France.
authors: P
authors: P
authors: Dalmas de Réotier
authors: A
authors: A
authors: Yaouanc
authors: P C M
authors: PC
authors: Gubbens
authors: C T
authors: CT
authors: Kaiser
authors: C
authors: C
authors: Baines
authors: P J C
authors: PJ
authors: King