arXiv subjects
Publications and source records attributed to D. N. Hendrickson.
The term in spin Hamiltonian, which determines the quantum tunneling rate in Mn12, is measured with neutron scattering. It is much smaller than previously reported values. This may imply that other mechanisms such as hyperfine fields may be more important in driving the tunneling.
We report point by point measurements below the blocking temperature of the magnetic relaxation of Mn$_{12}$-acetate as a function of magnetic field applied along the easy axis of magnetization. Unexpectedly complex structure is observed which we attribute to the effect of higher-order terms of the spin Hamiltonianon on the tunneling process.
We report zero-field inelastic neutron scattering experiments on a deuterated powder sample of Mn12-Acetate consisting of a large number of nominally identical spin-10 magnetic clusters. Our resolution enables us to see a series of peaks corresponding to transitions between the anisotropy levels within the spin-10 manifold. A fit to the spin Hamiltonian yields an anisotropy constant D=0.54 K and a fourth-order diagonal anisotropy coefficient A = 1.2x10^-3 K. Performed in the absence of a magnetic field, our experiments do not involve the g-values as fitting parameters, thereby yielding particularly reliable values of D and A.