Macroscopic Quantum Coherence in Small Antiferromagnetic Particle and the Quantum Interference Effects
- Starting from the Hamiltonian operator of the noncompensated two-sublattice model of a small antiferromagnetic particle, we derive the e 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.
Author: | Yi-Hang Nie, Y.-B. Zhang, J.-Q. Liang, H.J.W. Müller-Kirsten, F.-C. Pu |
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URN: | urn:nbn:de:hbz:386-kluedo-10960 |
Document Type: | Preprint |
Language of publication: | English |
Year of Completion: | 1999 |
Year of first Publication: | 1999 |
Publishing Institution: | Technische Universität Kaiserslautern |
Date of the Publication (Server): | 2001/02/09 |
Tag: | instanton method; level splitting; macroscopic quantum coherence |
Faculties / Organisational entities: | Kaiserslautern - Fachbereich Physik |
DDC-Cassification: | 5 Naturwissenschaften und Mathematik / 530 Physik |
Licence (German): | Standard gemäß KLUEDO-Leitlinien vor dem 27.05.2011 |