14 research outputs found
Magnetization switching in nanoscale ferromagnetic grains: simulations of heterogeneous nucleation
The phase diagram and the magnetic structure of nuclear spins in elemental copper below 60 nK
Magnetic excitations in the quasi one-dimensional antiferromagnetic singlet groundstate system CsFeBr3
Investigation of magnon dispersion relations and neutron scattering cross sections with special attention to anisotropy effects
Magnetization, magnetic susceptibility and ESR in Tb3Ga5O12
We report on the measurement of the magnetic susceptibility and of ESR transitions in the garnet substance Tb3Ga5O12 (TGG). The results are compared with a calculation in the framework of crystal field theory for the orthorhombic surroundings of the six inequivalent Tb ions of TGG. We also present a calculation of the magnetization for the three main crystal directions
Vibrational behavior of bcc Cu-based shape-memory alloys close to the martensitic transition
Simple solution to problems concerning oxygen ordering in YBa<sub>2</sub>Cu<sub>3</sub>O<sub>6</sub><sub>+</sub><sub>x</sub> (Erratum: Phys. Rev. B 61, 821, 2000)
Oxygen-ordering phenomena in YBa<sub>2</sub>Cu<sub>3</sub>O<sub>6</sub><sub>+</sub><sub>x</sub> studied by Monte Carlo simulation:PHASE-DIAGRAM, STRUCTURE FACTOR AND OXYGEN EQUILIBRIUM PRESSURE
The oxygen order in has been investigated by Monte Carlo simulation with the two-dimensional anisotropic next-nearest-neighbor lattice gas model, the ASYNNNI model. For a specific set of interaction parameters we have calculated the structural phase diagram, the chemical potential, and the structure factor as a function of temperature and wave vector for x=0.4. The phase diagram has been determined from an investigation of the order parameters and their fluctuations as well as by the use of an improved version of the Ferrenberg-Swendsen method. The calculated phase diagram and the widths of the structure factors are in excellent agreement with measured neutron-diffraction data. We suggest that the observation of an orthorhombic distortion, simultaneously with only short-range oxygen order at T=25°C, is due to the freezing-in of an ortho-II domain state with a preferred oxygen chain direction and accordingly only two types of domains. Using thermodynamic relations the chemical potential has been related to the measured oxygen-gas pressure, and it is discussed why only qualitative agreement with experimental data is established