313 research outputs found
TetraÂkis(μ-pivalato-κ2 O:O′)bisÂ[(2-methylÂpyridine-κN)iron(II)](Fe—Fe)
The asymmetric unit of the title compound, [Fe2(C5H9O2)4(C6H7N)2], contains one unique Fe-atom site located close to a centre of symmetry which generates the molÂecular dimer. The two Fe atoms are bridged by four carboxylÂate groups and are each coordinated by a molÂecule of 2-picoline. Electron counting and the 18-electron rule suggest that a chemical single bond is likely to exist between the two Fe atoms, which are separated by a distance of 2.8576 (4) Å. This bond completes an approximately octaÂhedral coordination environment around each Fe atom
Will spin-relaxation times in molecular magnets permit quantum information processing?
Using X-band pulsed electron spin resonance, we report the intrinsic
spin-lattice () and phase coherence () relaxation times in molecular
nanomagnets for the first time. In Cr heterometallic wheels, with = Ni
and Mn, phase coherence relaxation is dominated by the coupling of the electron
spin to protons within the molecule. In deuterated samples reaches 3
s at low temperatures, which is several orders of magnitude longer than
the duration of spin manipulations, satisfying a prerequisite for the
deployment of molecular nanomagnets in quantum information applications.Comment: 4 pages, 3 figures, in press at Physical Review Letter
g-engineering in hybrid rotaxanes to create AB and AB2 electron spin systems: EPR spectroscopic studies of weak interactions between dissimilar electron spin qubits
Hybrid [2]rotaxanes and pseudorotaxanes are reported where the magnetic interaction between dissimilar spins is controlled to create AB and AB2 electron spin systems,allowing independent control of weakly interacting S =1=2 centers
Synthesis and Structural, Magnetic and EPR Characterization of Discrete Finite Antiferromagnetic Chains
Spin dynamics of molecular nanomagnets fully unraveled by four-dimensional inelastic neutron scattering
Molecular nanomagnets are among the first examples of spin systems of finite
size and have been test-beds for addressing a range of elusive but important
phenomena in quantum dynamics. In fact, for short-enough timescales the spin
wavefunctions evolve coherently according to the an appropriate cluster
spin-Hamiltonian, whose structure can be tailored at the synthetic level to
meet specific requirements. Unfortunately, to this point it has been impossible
to determine the spin dynamics directly. If the molecule is sufficiently
simple, the spin motion can be indirectly assessed by an approximate model
Hamiltonian fitted to experimental measurements of various types. Here we show
that recently-developed instrumentation yields the four-dimensional
inelastic-neutron scattering function S(Q,E) in vast portions of reciprocal
space and enables the spin dynamics to be determined with no need of any model
Hamiltonian. We exploit the Cr8 antiferromagnetic ring as a benchmark to
demonstrate the potential of this new approach. For the first time we extract a
model-free picture of the quantum dynamics of a molecular nanomagnet. This
allows us, for example, to examine how a quantum fluctuation propagates along
the ring and to directly test the degree of validity of the
N\'{e}el-vector-tunneling description of the spin dynamics
Varying spin state composition by the choice of capping ligand in a family of molecular chains: detailed analysis of magnetic properties of chromium(III) horseshoes
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