Pressure-Induced Reentrant Oblique Antiferromagnetic Phase in Spin Dimer System TlCuCl_3

Abstract

Magnetization measurements under a hydrostatic pressure of P = 1.4 GPa were performed on the coupled spin dimer system TlCuCl_3, which exhibits a pressure-induced quantum phase transition from a gapped singlet state to an antiferromagnetic state at P_c = 0.042 GPa. Antiferromagnetic ordering with ordered moments parallel to the ac plane was observed at T_N = 16.7 K at 1.4 GPa. The spin reorientation phase transition was observed at T_R ~ 9.2 K for zero magnetic field, at which the ordered moments start to incline towards the b axis. With increasing external field parallel to th b axis, a second-order phase transition from the oblique antiferromagnetic (OAF) phase to the spin-flop (SF) phase occurs below T_R. We argue that the OAF phase arises from the competition between the anisotropic energies of the conventional second order and the fourth order, that increases with increasing pressure. We discuss the OAF-SF transition within the framework of the mean field approximation.

7 pages, 7 figures

References in corpus (8)

• Bose-Einstein Condensation in Magnetic Insulators
• Quantum magnetism and criticality
• Quantum Magnets under Pressure: Controlling Elementary Excitations in TlCuCl3
• Bose-Einstein Condensation of Magnons in TlCuCl3: Phase diagram and specific heat from a self-consistent Hartee-Fock calculation with a realistic dispersion relation
• Spin-resonance modes of the spin-gap magnet TlCuCl_3
• Field-driven phase transitions in a quasi-two-dimensional quantum antiferromagnet
• Pressure-Induced Magnetic Quantum Phase Transition in Gapped Spin System KCuCl3
• Softening of Magnetic Excitations Leading to Pressure-Induced Quantum Phase Transition in Gapped Spin System KCuCl${}_3$