EFFECT OF A TRANSVERSE MAGNETIC-FIELD ON RESONANT MAGNETIZATION TUNNELING IN HIGH-SPIN MOLECULES

The recent observation of steps at regular intervals of magnetic field in the hysteresis loops of oriented crystals of the spin-10 molecular magnet Mn12O12(CH3COO)(16)(H2PO)(4) has been attributed to resonant t unneling between spin states. Here, we investigate the effect on the r elaxation rate of applying the magnetic field at an angle with respect to the easy axis of magnetization. We find that the position of the r esonances is independent of the transverse component of the field, and is determined solely by the longitudinal component. On the other hand , a transverse field significantly increases the relaxation rate, both on and off resonance. We discuss classical and quantum-mechanical int erpretations of this effect. (C) 1997 American Institute of Physics.