Absence of Conventional Spin-Glass Transition in the Ising Dipolar System LiHo x Y 1 − x F 4

P. E. Jönsson (1) , R. Mathieu (2) , W. Wernsdorfer (3) , A. M. Tkachuk (4) , B. Barbara (3)

1 Uppsala University
2 KTH - KTH Royal Institute of Technology [Kista]
3 NEEL - QuantECA - Circuits électroniques quantiques Alpes
4 S. I. Vavilov State Optical Institute

The magnetic properties of single crystals of LiHoxY1-xF4 with x = 16:5% and x = 4:5% were recorded down to 35 mK using a micro-SQUID magnetometer. While this system is considered as the archetypal quantum spin glass, the detailed analysis of our magnetization data indicates the absence of a phase transition, not only in a transverse applied magnetic field, but also without field. A zero-Kelvin phase transition is also unlikely, as the magnetization seems to follow a noncritical exponential dependence on the temperature. Our analysis thus unmasks the true, short-ranged nature of the magnetic properties of the LiHoxY1-xF4 system, validating recent theoretical investigations suggesting the lack of phase transition in this system.

Domaines: Matière Condensée [cond-mat]

P. E. Jönsson, R. Mathieu, W. Wernsdorfer, A. M. Tkachuk, B. Barbara. Absence of Conventional Spin-Glass Transition in the Ising Dipolar System LiHo x Y 1 − x F 4. Physical Review Letters, 2007, 98 (25), pp.256403. ⟨10.1103/PhysRevLett.98.256403⟩. ⟨hal-01660159⟩