First- and second-order crossovers of the escape rate in single-molecule magnet with a biaxial symmetry

Quantum-classical escape rate crossover has been studied for a biaxial nanomagnetic system. Employing numerical diagonalization approach and using the simple quantum transition state theory, we have obtained the boundary separating the first- and the second-order crossover and the escape rate in the presence of a magnetic field along the medium axis. The results are expected to be tested in existing experimental techniques.