Muon spin rotation studies of spin dynamics at avoided level crossings in LiY0.998Ho0.002F4.
We have studied the Ho3+ spin dynamics for LiY0.998Ho0.002F4 via the positive muon (mu+) transverse field depolarization rate lambdaTF as a function of temperature and magnetic field. We find sharp minima in lambdaTF(H) at fields for which the Ho3+ ion system has field-induced (avoided) level crossings. The reduction scales with calculated level repulsions, suggesting that mu+ depolarization by slow fluctuations of nonresonant Ho3+ spin states is partly suppressed when resonant tunneling opens new fluctuation channels at frequencies much greater than the muon precession frequency.
Graf
M J
MJ
Department of Physics, Boston College, Chestnut Hill, Massachusetts 02467, USA.
Lago
J
J
Lascialfari
A
A
Amato
A
A
Baines
C
C
Giblin
S R
SR
Lord
J S
JS
Tkachuk
A M
AM
Barbara
B
B