Butterfly hysteresis curve is a signature of adiabatic Landau-Zener transition

Vogelsberger, Mark; Garanin, D. A.; Schilling, Rolf

Butterfly hysteresis curve is a signature of adiabatic Landau-Zener transition

Authors

Vogelsberger, Mark

Garanin, D. A.

Schilling, Rolf

Description

We stress that the so-called butterfly hysteresis curves observed in dynamical magnetization measurements on systems of low-spin magnetic molecules such as V-15 and V-6 are a signature of adiabatic Landau-Zener transitions rather than that of a phonon bottleneck. We investigate the magnetization dynamics analytically with the help of a simple relaxation theory in the basis of the adabatic energy levels of the spin 1/2, to a qualitative accordance with experimental observations. In particular, reversible behavior is found near zero field, the corresponding susceptibility being bounded by the equilibrium and adiabatic susceptibilities from below and above, respectively.
4 PR pages, 5 figures