The antiferromagnetic three-state Potts model on the simple-cubic lattice is studied using Monte Carlo simulations. The ordering in a medium temperature range below the critical point is investigated in detail. Two di erent regimes have been observed: The so-called broken sublattice-symmetry phase dominates at su ciently low temperatures, while the phase just below the critical point is charact...

Free-standing BiFeO3 perovskite particles with a size ranging from polycrystalline bulk down to 5 nm have been studied by high-energy resonant (Bi K edge) x-ray diffraction coupled to differential atomic pair distribution function analysis. Nanosized BiFeO3 particles are found to exhibit extra, i.e., beyond the usual thermal, structural disorder that increases progressively with diminishing the...

is finite, where λ denotes Lebesgue measure. Let ρ be the gauge functional of the convex hull of the unit ball {f : q(f) ≤ 1} of the quasi-norm q, and let N be the null space of ρ. The normed envelope of WeakL, which we denote by W , is the space (WeakL/N, ρ). The Banach envelope of WeakL, W , is the completion of W . We show that W is isometrically lattice isomorphic to a sublattice of W . It ...

The article contains computational data of electronic structure and crystal stability of two sigma-phases, namely Fe-Cr-Co and Fe-Cr-Ni, using the Korringa-Kohn-Rostoker method (KKR) for electronic band structure calculations. Total energy values, ET , calculated for the number of ordered unit cells with various atomic concentrations and sublattice occupancies are reported. In parallel, obtaine...

We consider the iron pnictides in terms of a proximity to a Mott insulator. The superexchange interactions contain competing nearest-neighbor and next-nearest-neighbor components. In the undoped parent compound, these frustrated interactions lead to a two-sublattice collinear antiferromagnet (each sublattice forming a Néel ordering), with a reduced magnitude for the ordered moment. Electron or ...

Using the PVM programming environment for parallel applications, we have parallelized a simulation of the two{dimensional Ising Model on a cluster of IBM RISC System/60001 workstations connected by a Token Ring (16Mb/sec) and by Serial Optical Channels (220 Mb/sec) via a NSC2 DX Router. The parallelization is done by dividing the lattice into sublattices, each sublattice being associated with o...

The diruthenium compound [Ru(2)(O(2)CMe)(4)](3)[Cr(CN)(6)] contains two weakly coupled, ferrimagnetically ordered sublattices occupying the same volume. Due to the weak, antiferromagnetic dipolar interaction K(c) ≈ 5 × 10(-3) meV between sublattices, a small magnetic field H(c) ∼ K(c)/μ(B) ≈ 800 Oe aligns the sublattice moments. Powder neutron-diffraction measurements on a deuterated sample co...

Lenstra, Lenstra, and Lovász in [7] proved several inequalities showing that the vectors in an LLL-reduced basis are short, and near orthogonal. Here we present generalizations, from which with k = 1, and k = n we can recover their inequalities: Theorem 1. Let b1, . . . , bn ∈ R be an LLL-reduced basis of the lattice L, and d1, . . . , dk arbitrary linearly independent vectors in L. Then ‖b1 ‖ ...

Canonical extensions of lattice ordered algebras provide an algebraic formulation of what is otherwise treated via topological duality or relational methods. They were firstly introduced by Jónsson and Tarski for Boolean algebras with operators (see [8] and [9]) and generalized for distributive lattices with different operations in [5], [4] and [3]. If A = (A, {fi, i ∈ I}) is a distributive lat...