Related papers: Macroscopic quantum coherence in antiferromagnetic…
We study the quantum dynamics of polygonal rare-earth molecular clusters with Ising-type ion magnetization. It is shown that the ground state of such systems is a non-magnetic quasi-doublet of states with oppositely twisted ion spins. The…
We study the effect of a strong electron-electron (e-e) interaction in a system of two concentric one-dimensional rings with incommensurate areas A_1 and A_2, coupled by a tunnel amplitude. For noninteracting particles the magnetic moment…
We investigate quantum phase transitions and quantum coherence in infinite biquadratic spin-1 and -2 XY chains with rhombic single-ion anisotropy. All considered coherence measures such as the $l_1$ norm of coherence, the relative entropy…
The quantum-classical transitions of the escape rates in a uniaxial spin model relevant to the molecular magnet Mn$_{12}$Ac and a biaxial anisotropic ferromagnetic particle are investigated by applying the periodic instanton method. The…
Carbon-based nanostructures possessing {\pi}-electron magnetism have attracted tremendous interest due to their great potential for nano spintronics. In particular, quantum chains with magnetic molecular units synthesized by on-surface…
We study electronic transport through a magnetic molecule with an intrinsic spin $S$ coupled to two magnetic electrodes, in the incoherent regime. The molecule is modeled as a single resonant level with large Coulomb repulsion (no double…
The molecule-based magnet [Ru$_2$(O$_2$CMe)$_4$]$_3$[Cr(CN)$_6$] contains two weakly-coupled, interpenetrating sublattices in a body-centered cubic structure. Although the field-dependent magnetization indicates a metamagnetic transition…
The antiferromagnetic Heisenberg model on the icosahedron, which consists of 20 edge-sharing triangles and belongs to the icosahedral $I_h$ symmetry group, presents unconventional properties at the classical and quantum level. These…
Several quantum critical compounds have been argued to have multiple instabilities towards orders with distinct dynamical exponents. We present an analysis of a quantum multicritical point in an itinerant magnet with competition between…
We study the magnetoconductance of electrons through a mesoscopic channel with antidots. Through quantum interference effects, the conductance maxima as functions of the magnetic field strength and the antidot radius (regulated by the…
In magnetic topological insulators, spontaneous time-reversal symmetry breaking by intrinsic magnetic order can gap the topological surface spectrum, resulting in exotic properties like axion electrodynamics, the quantum anomalous Hall…
The antiferromagnetic Heisenberg model on icosahedral symmetry $I_{h}$ fullerene clusters exhibits unconventional magnetic properties, despite the lack of anisotropic interactions. At the classical level, and for number of sites $n \leq…
It is shown that magnetic states and field-driven reorientation transitions in synthetic antiferromagnets crucially depend on contributions of higher-order anisotropies. A phenomenological macrospin model is derived to describe the magnetic…
Transport and non-equilibrium magnetization in monolayers of magnetic molecules subject to a bias voltage are considered. We apply a master-equation approach going beyond the sequential-tunneling approximation to study the Coulomb-blockade…
Magnetization processes of the spin-1/2 antiferromagnetic $XXZ$ model in two and three spatial dimensions are studied using quantum Monte Carlo method based on stochastic series expansions. Recently developed operator-loop algorithm enables…
The symmetry of magnetic quantum tunneling has been studied in the prototype single molecule magnet Mn$_{12}$-acetate using a micro-Hall effect magnetometer and superconducting high field vector magnet system. An average crystal fourfold…
Asymmetric magnetization reversal is an unusual phenomenon in antiferromagnet / ferromagnet (AF/FM) exchange biased bilayers. We investigated this phenomenon in a simple model system experimentally and by simulation assuming inhomogeneously…
The asymmetric magnetization reversal is studied in a single exchange-biased microbar of 1.5 x 13 micrometer with anisotropic magnetoresistance and magnetic force microscopy. The particle has a moment of less than 10^-9 emu and is not…
This is a review of ground-state features of the s=1/2 Heisenberg antiferromagnet on two-dimensional lattices. A central issue is the interplay of lattice topology (e.g. coordination number, non-equivalent nearest-neighbor bonds, geometric…
Making use of exact results and quantum Monte Carlo data for the entanglement of formation, we show that the ground state of anisotropic two-dimensional S=1/2 antiferromagnets in a uniform field takes the classical-like form of a product…