https://doi.org/10.1140/epjb/e20020117
Spin tunneling properties in mesoscopic magnets: effects of a magnetic field
Center for Advanced Study, Tsinghua University,
Beijing 100084, PR China
Corresponding author: a rlu@castu.tsinghua.edu.cn
Received:
12
March
2001
Revised:
18
October
2001
Published online: 15 April 2002
The tunneling of a giant spin at excited levels
is studied theoretically in
mesoscopic magnets with
a magnetic field at an arbitrary angle in the easy plane.
Different structures of the tunneling barriers
can be generated by the magnetocrystalline
anisotropy, the magnitude and the orientation
of the field.
By calculating the nonvacuum instanton solution explicitly,
we obtain the tunnel splittings and the
tunneling rates for different angle ranges of the external magnetic field
(
and 
).
The temperature dependences of
the decay rates are clearly shown for each case.
It is found that the tunneling rate and
the crossover temperature depend on the
orientation of the external magnetic
field. This feature can be tested with the
use of existing experimental techniques.
PACS: 75.45.+j – Macroscopic quantum phenomena in magnetic systems / 75.50.Mm – Magnetic liquids
© EDP Sciences, Società Italiana di Fisica, Springer-Verlag, 2002
