H. Shtrikman

Distribution of Tunnel Splittings in Mn12 Acetate

In magnetic fields applied parallel to the anisotropy axis, the relaxation of the magnetization of Mn(12)-acetate measured for different sweep rates collapses onto a single scaled curve. The form of the scaling implies that the dominant symmetry-breaking process responsible for tunneling is a locally varying second-order transverse anisotropy, forbidden by tetragonal symmetry in the perfect crystal, which gives rise to a broad distribution of tunnel splittings in a real crystal of Mn(12) acetate. Different forms applied to even- and odd-numbered steps provide a clear distinction between even resonances (associated with crystal anisotropy) and odd resonances (which require a transverse magnetic field).

Propagation of Avalanches in Mn12-acetate: Magnetic Deflagration

Local time-resolved measurements of fast reversal of the magnetization of single crystals of Mn12-acetate indicate that the magnetization avalanche spreads as a narrow interface that propagates through the crystal at a constant velocity that is roughly 2 orders of magnitude smaller than the speed of sound. We argue that this phenomenon is closely analogous to the propagation of a flame front (deflagration) through a flammable chemical substance.

Propagation of Avalanches inMn12-Acetate: Magnetic Deflagration

Local time-resolved measurements of fast reversal of the magnetization of single crystals of Mn12-acetate indicate that the magnetization avalanche spreads as a narrow interface that propagates through the crystal at a constant velocity that is roughly 2 orders of magnitude smaller than the speed of sound. We argue that this phenomenon is closely analogous to the propagation of a flame front (deflagration) through a flammable chemical substance.

Mn12-acetate: a prototypical single molecule magnet

Abstract Single molecule magnets display fascinating quantum mechanical behavior, and may have important technological applications for information storage and quantum computation. A brief review is given of the physical properties of Mn12-acetate, one of the two prototypical molecular nanomagnets that have been most intensively investigated. Descriptions and discussions are given of the Mn12 magnetic cluster and the fundamental process of quantum tunneling of a nanoscopic spin magnetization; the distinction between thermally-assisted tunneling and pure quantum tunneling, and a study of the crossover between the two regimes; and a review of earlier investigations that suggest that the tunneling in this system is due to locally varying second-order crystal anisotropy which gives rise to a distribution of tunnel splittings. In the second part of the paper, we report results obtained by a new experimental method that confirm our earlier conclusion that the tunnel splittings in Mn12 are distributed rather than single-valued, as had been generally assumed.

Surface barrier dominated transport in NbSe2

Transport current distribution in clean

Photon-induced magnetization reversal in the Fe8 single-molecule magnet

{2mathrm{H}ensuremath{-}mathrm{N}mathrm{b}mathrm{S}mathrm{e}}_{2}

Absorption Spectrum Around nu = 1: Evidence for a Small-Size Skyrmion

crystals is studied by measuring the self-induced magnetic field across the sample. Below

Experimental determination of the dipolar field in Mn

{T}_{c}

_{12}

most of the current flows at the edges of the crystals due to strong surface barriers, which are found to dominate the transport properties and the resistive transition. The measured critical current is determined by the critical current for vortex penetration through the surface barrier rather than by bulk pinning.

-acetate

We use millimeter-wave radiation to manipulate the populations of the energy levels of a single crystal of molecular magnet Fe8. When continuous-wave radiation is in resonance with the transition from the ground state to the first excited state, the equilibrium magnetization exhibits a peak or dip whose field position varies linearly with the radiation frequency. Our results provide a lower bound of 0.17 ns for transverse relaxation time and suggest the possibility that single-molecule magnets might be utilized for quantum computation.