Macroscopic Quantum Coherence in Small Antiferromagnetic Particle and the Quantum Interference Effects
Abstract
Starting from the Hamiltonian operator of the noncompensated two-sublattice model of a small antiferromagnetic particle, we derive the effective Lagrangian of a biaxial antiferromagnetic particle in an external magnetic field with the help of spin-coherent-state path integrals. Two unequal level-shifts induced by tunneling through two types of barriers are obtained using the instanton method. The energy spectrum is found from Bloch theory regarding the periodic potential as a superlattice. The external magnetic field indeed removes Kramers' degeneracy, however a new quenching of the energy splitting depending on the applied magnetic field is observed for both integer and half-integer spins due to the quantum interference between transitions through two types of barriers.
Keywords
Cite
@article{arxiv.cond-mat/9909371,
title = {Macroscopic Quantum Coherence in Small Antiferromagnetic Particle and the Quantum Interference Effects},
author = {Y. -H. Nie and Y. -B. Zhang and J. -Q. Liang and H. J. W. Mueller-Kirsten and F. -C. Pu},
journal= {arXiv preprint arXiv:cond-mat/9909371},
year = {2009}
}
Comments
9 pages, Latex, 4 Postscript figures