相关论文: Macroscopic Quantum Coherence in Molecular Magnets

Coherent resonant tunneling through an artificial molecule of quantum dots in an inhomogeneous magnetic field is investigated using an extended Hubbard model. Both the multiterminal conductance of an array of quantum dots and the persistent…

A Mn30 molecular cluster is established to be the largest single-molecule magnet (SMM) discovered to date. Magnetization versus field measurements show coercive fields of about 0.5 T at low temperatures. Magnetization decay experiments…

The quantum tunneling of the magnetization vector are studied theoretically in single-domain ferromagnetic nanoparticles placed in an external magnetic field at an arbitrarily directed angle in the $ZX$ plane. We consider the…

Magnetic quantum tunneling in a single molecule magnet (SMM) has been studied in experiments that combine microwave spectroscopy with high sensitivity magnetic measurements. By monitoring spin-state populations in the presence of microwave…

We measure the low-temperature resistance of permalloy break junctions as a function of contact size and the magnetic field angle, in applied fields large enough to saturate the magnetization. For both nanometer-scale metallic contacts and…

We study theoretically the spin dynamics of the ferric wheel, an antiferromagnetic molecular ring. For a single nuclear or impurity spin coupled to one of the electron spins of the ring, we calculate nuclear and electronic spin correlation…

Quantum phase interference and spin-parity effects are studied in biaxial molecular magnets in a magnetic field at an arbitrarily directed angle. The calculations of the ground-state tunnel splitting are performed on the basis of the…

In recent years, studies on cyclic molecular nanomagnets have captivated the attention of researchers. These magnets are finite in size and contain very large spins. They are interesting because they possess macroscopic quantum tunneling of…

Field-tuned quantum tunneling in two single-molecule magnets coupled antiferromagnetically and formed a supramolecule dimer is studied. We obtain step-like magnetization curves by means of the numerically exact solution of the…

Molecular nanomagnets, besides promising to open new frontiers in technology, have attracted huge interest in the scientific community because they can exhibit the phenomenon known as quantum tunnelling of the magnetization, i.e. coherent…

Single-site measurement in a distributed macroscopic antiferromagnet is considered; we show that it can create antiferromagnetic sublattices at macroscopic scale. We demonstrate that the result of measurement depends on the symmetry of the…

Small ferromagnets and anti-ferromagnets with an easy-plane anisotropy have a ground to first excited state (tunnel) splitting which is quasi-periodic in the magnitude of a field applied perpendicular to a principal anisotropy axis. The…

This chapter takes a microscopic view of quantum tunneling of magnetization (QTM) in single-molecule magnets (SMMs), focusing on the interplay between exchange and anisotropy. Careful consideration is given to the relationship between…

The quantum tunneling of the magnetization vector between excited levels are studied theoretically in single-domain ferromagnetic nanoparticles with biaxial crystal symmetry placed in an external magnetic field at an arbitarily directed…

A Mn4 single-molecule magnet (SMM) is used to show that quantum tunneling of magnetization (QTM) is not suppressed by moderate three dimensional exchange coupling between molecules. Instead, it leads to an exchange bias of the quantum…

Two single-molecule magnets are coupled antiferromagnetically to form a supramolecule dimer. We study the coupling effect and tunneling process by means of the numerical exact diagonalization method, and apply them to the recently…

A new quantum approach is presented that can account for the description of small ferromagnetic particles magnetization tunneling. An estimate of the saturation value of an external applied magnetic field along the easy axis is obtained. An…

For a number of quantum critical points in one dimension quantum field theory has provided exact results for the scaling of spatial and temporal correlation functions. Experimental realizations of these models can be found in certain quasi…

Coherent spin-dependent electronic transport is investigated in a molecular junction made of polymeric chain attached to ferromagnetic electrodes (Ni and Co, respectively). Molecular system is described by a simple Huckel model, while the…

At finite temperature we study the quantum tunneling of magnetization for a small ferromagnetic particle with the biaxial symmetry placed in a magnetic field at an arbitrary angle. We present numerical WKB exponent below the crossover…