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We study theoretically the thermodynamic properties and spin dynamics of a class of magnetic rings closely related to ferric wheels, antiferromagnetic ring systems, in which one of the Fe (III) ions has been replaced by a dopant ion to…

Mesoscale and Nanoscale Physics · Physics 2009-11-07 Florian Meier , Daniel Loss

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…

Mesoscale and Nanoscale Physics · Physics 2009-11-07 Florian Meier , Daniel Loss

From inelastic neutron scattering experiments, we demonstrate quantum tunneling of the Neel vector in the antiferromagnetic molecular ferric wheel CsFe8. Analysis of the linewidth of the tunneling transition evidences coherent tunneling.

Mesoscale and Nanoscale Physics · Physics 2009-11-10 O. Waldmann , C. Dobe , H. Mutka , A. Furrer , H. U. Güdel

The detailed theoretical understanding of quantum spin dynamics in various molecular magnets is an important step on the roadway to technological applications of these systems. Quantum effects in both ferromagnetic and antiferromagnetic…

Mesoscale and Nanoscale Physics · Physics 2007-05-23 Michael N. Leuenberger , Florian Meier , Daniel Loss

The spin correlations \omega^z_r, r=1,2,3, and the probability p_N$ of finding a system in the Neel state for the antiferromagnetic ring Fe(III)6 (the so-called `small ferric wheel') are calculated. States with magnetization M=0, total spin…

Mesoscale and Nanoscale Physics · Physics 2009-11-07 Wojciech Florek , Sylwia Bucikiewicz

The low-temperature elementary spin excitations in the AFM molecular wheel Fe18 were studied experimentally by inelastic neutron scattering and theoretically by modern numerical methods, such as dynamical density matrix renormalization…

Spin tunneling in the particular case of the magnetic molecular cluster octanuclear iron(III), Fe8, is treated by an effective Hamiltonian that allows for an angle-based description of the process. The presence of an external magnetic field…

Quantum Physics · Physics 2009-11-13 D. Galetti , E. C. Silva

We investigate the role of topology and distortions in the quantum dynamics of magnetic molecules, using a cyclic spin system as reference. We consider three variants of antiferromagnetic molecular ring, i.e. Cr$_8$, Cr$_7$Zn and Cr$_7$Ni,…

Mesoscale and Nanoscale Physics · Physics 2009-11-10 S. Carretta , P. Santini , G. Amoretti , M. Affronte , A. Ghirri , I. Sheikin , S. Piligkos , G. Timco , R. E. P. Winpenny

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…

Mesoscale and Nanoscale Physics · Physics 2015-06-11 M. L. Baker , T. Guidi , S. Carretta , J. Ollivier , H. Mutka , H. U. Güdel , G. A. Timco , E. J. L. McInnes , G. Amoretti , R. E. P. Winpenny , P. Santini

The inelastic neutron scattering (INS) spectrum is studied for the antiferromagnetic molecular wheel CsFe8, in the temperature range 2 - 60 K, and for transfer energies up 3.6 meV. A qualitative analysis shows that the observed peaks…

Strongly Correlated Electrons · Physics 2009-11-11 O. Waldmann , C. Dobe , H. U. Güdel , H. Mutka

We study spin tunneling in magnetic molecules, with special reference to Fe8. The article aims to give a pedagogical discussion of what is meant by the tunneling of a spin, and how tunneling amplitudes or energy level splittings may be…

Mesoscale and Nanoscale Physics · Physics 2007-05-23 Anupam Garg

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…

Mesoscale and Nanoscale Physics · Physics 2015-05-29 S. A. Owerre , J. Nsofini

Based on first-principles density-functional theory calculations we investigate the electronic structure of hexanuclear "ferric wheels" M Fe_6[N(CH_2 CH_2 O)_3]_6 Cl (M = Li, Na) in their antiferromagnetic ground state. The electronic…

Materials Science · Physics 2007-05-23 A. V. Postnikov , Jens Kortus , Stefan Bluegel

The spin-phase interference effects are studied analytically in resonant quantum tunneling of the N\'{e}el vector between degenerate excited levels in nanometer-scale single-domain antiferromagnets in the absence of an external magnetic…

Statistical Mechanics · Physics 2015-06-24 Rong Lu , Jia-Lin Zhu , Yi Zhou , Bing-Lin Gu

Using an efficient numerical scheme that exploits spatial symmetries and spin-parity, we have obtained the exact low-lying eigenstates of exchange Hamiltonians for ferric wheels up to Fe$_{12}$. The largest calculation involves the…

Mesoscale and Nanoscale Physics · Physics 2009-11-07 Indranil Rudra , S. Ramasesha , Diptiman Sen

The Li-centered "ferric wheel" molecules with six oxo-bridged iron atoms form molecular crystals. We probed their electronic structure by X-ray photoelectron (XPS) and soft X-ray emission spectroscopy (XES), having calculated in parallel…

Materials Science · Physics 2009-11-10 A. V. Postnikov , S. G. Chiuzbaian , M. Neumann , S. Bluegel

The antiferromagnetic molecular wheel Fe18 of eighteen exchange-coupled Fe(III) ions has been studied by measurements of the magnetic torque, the magnetization, and the inelastic neutron scattering spectra. The combined data show that the…

Strongly Correlated Electrons · Physics 2015-05-13 O. Waldmann , T. C. Stamatatos , G. Christou , H. U. Güdel , I. Sheikin , H. Mutka

The organometallic ring molecules Fe_6 and Fe_10 are leading examples of a class of nanoscopic molecular magnets, which have been of intense recent interest both for their intrinsic magnetic properties and as candidates for the observation…

Mesoscale and Nanoscale Physics · Physics 2009-10-31 B. Normand , X. Wang , X. Zotos , Daniel Loss

Electrical control of spins at the nanoscale offers significant architectural advantages in spintronics, because electric fields can be confined over shorter length scales than magnetic fields. Thus, recent demonstrations of electric-field…

Mesoscale and Nanoscale Physics · Physics 2021-10-15 Junjie Liu , Jakub Mrozek , Aman Ullah , Yan Duan , José J. Baldoví , Eugenio Coronado , Alejandro Gaita-Ariño , Arzhang Ardavan

Spin-electronic devices are poised to become part of mainstream microelectronic technology .Downsizing them, however, faces the intrinsic difficulty that as ferromagnets become smaller, it becomes more difficult to stabilize their magnetic…

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