Escape rate of a biaxial nanospin system in a magnetic field : first- and second-order transition between quantum and classical regimes

Abstract

We investigate the escape rate of the biaxial nanospin particle with a magnetic field applied along the easy axis. The model studied here is described by the Hamiltonian $\mathcal{H}=-A{S}_z^2-B{S}_x^2-H{S}_z,(A>B>0)$. By reducing this Hamiltonian to a particle one, we derive, for the first time, an effective particle potential for this model and find an analytical form of the phase boundary line between first- and second-order transitions, from which a complete phase diagram can be obtained. We also derive an analytical form of the crossover temperature as a function of the applied field at the phase boundary.

8pages, 3figures

References in corpus (5)

• First- and Second-Order Transitions between Quantum and Classical Regimes for the Escape Rate of a Spin System
• Quantum-Classical Transition of the Escape Rate of a Uniaxial Spin System in an Arbitrarily Directed Field
• Periodic Instantons and Quantum-Classical Transitions in Spin Systems
• Quantum-Classical Escape-Rate Transition of a Biaxial Spin System with a Longitudinal Field: a Perturbative Approach
• Quantum Tunneling and Phase Transitions in Spin Systems with an Applied Magnetic Field

Cited by in corpus (3)

• Macroscopic quantum tunneling and quantum-classical phase transitions of the escape rate in large spin systems
• First- and second-order transitions of the escape rate in ferrimagnetic or antiferromagnetic particles
• Bifurcation of Periodic Instanton in Decay-Rate Transition