Magnetization of small ferromagnetic clusters at finite temperatures has been studied using the Ising model and Monte Carlo techniques. The magnetization is reduced from bulk value, increases with external magnetic field cluster size. results explain qualitatively recent observations by de Heer, Milani, Chatelain reduction decreasing size average moment in iron clusters.

Results of experiments on the dynamics and kinetic roughening one-dimensional slow-combustion fronts in three grades paper are reported. Extensive averaging data allows a detailed analysis spatial temporal development interface fluctuations. The asymptotic scaling properties, long length time scales, well described by Kardar-Parisi-Zhang (KPZ) equation with short-range, uncorrelated noise. To obtain more picture strong-coupling fixed point, characteristic KPZ universality class, universal...

We present Monte Carlo simulations for the size and temperature dependence of diffusion coefficient adatom islands on Cu(100) surface. show that scaling exponent is not a constant but decreasing function island approaches unity very large islands. This due to crossover from periphery dominated mass transport regime where vacancies diffuse inside island. The effective exponents are in good agreement with theory experiments.

The spatial and temporal persistence, or first-return distributions are measured for slow-combustion fronts in paper. stationary (perhaps less convincingly) persistence exponents agree with the predictions based on front dynamics, which asymptotically belongs to Kardar-Parisi-Zhang universality class. short-range transient behavior of non-Markovian, observed properties thus do not Markovian theory. This deviation is a consequence additional time length scales, related crossovers asymptotic...

We consider adatom dynamics and diffusion in a lattice-gas model of the O/W(110) system under conditions where interaction effects are important. In particular, we study behavior tracer collective coefficients as function temperature when crossing over from high-temperature disordered phase to low-temperature symmetry broken phase. To this end, utilize combined analytical numerical approach based on recently developed dynamical mean field theory (DMF) addition conventional Monte Carlo...

We study the non-Arrhenius behavior of surface diffusion near second-order phase transition boundary an adsorbate layer. In contrast to expectations based on macroscopic thermodynamic effects, we show that this can be related average microscopic jump rate which in turn is determined by waiting-time distribution W(t) single-particle jumps at short times. At long times, yields a barrier corresponds rate-limiting step diffusion. The information should accessible STM measurements.

The structure of the Cu(110) surface is studied at high temperatures using a combination lattice-gas Monte Carlo and molecular dynamics methods with identical many-atom interactions derived from effective-medium theory. A clear roughening transition found around 1000 K. rough phase identified logarithmic divergence height-height correlation function. mechanism connected formation thermally generated diffusive clusters both adatom vacancy type.

We present a memory expansion for macroscopic transport coefficients such as the collective and tracer diffusion ${D}_{C}$ ${D}_{T},$ respectively. The successive terms in this describe rapidly decaying effects of center-of-mass motion, leading to fast convergence when evaluated numerically. For one obtains an similar form that contains describing single-particle motion. As example we evaluate ${D}_{T}$ three strongly interacting surface systems through Monte Carlo simulations, simple model...

The in-plane thermal conductivity of porous sintered bronze plates was studied both experimentally and numerically. We developed validated an experimental setup, where the sample placed in vacuum heated while its time-dependent temperature field measured with infrared camera. porosity detailed three-dimensional structure samples were determined by X-ray microtomography. Lattice-Boltzmann simulations tomographic reconstructions used to correct contact area between particles as image analysis...

We study the dynamics of adatoms in a model vicinal (11m) fcc metal surfaces. examine role different diffusion mechanisms and their implications to surface growth. In particular, we effect steps kinks on adatom dynamics. show that existence is crucially important for motion along across steps. Our results are agreement with recent experiments Cu(100) Cu(1,1,19) The also suggest that, some metals, exotic may be mass transport

We study collective diffusion of adatoms on a stepped substrate within Langmuir gas model. Our model allows for modified potential barriers and wells near the step edges, as well different prefactors intrinsic jump rates at edges. The tensor is calculated using projection operator techniques. in detail dependence macroscopic microscopic parameters Collective effects due to finite coverage turn out be crucial determining influence steps measurable activation effective already low coverage.

We study the coverage dependence of surface diffusion coefficients for a strongly interacting adsorption system O/W(110) via Monte Carlo simulations lattice-gas model. In particular, we consider nature and emergence memory effects as contained in corresponding correlation factors tracer collective diffusion. show that can be very pronounced deep inside ordered phases regions close to first second order phase transition boundaries. Particular attention is paid details time effects. The effect...

The (110)(1*2) missing-row reconstruction of the seven FCC metals Ni, Pd, Pt, Cu, Ag, Au and Al has been studied using effective medium theory (EMT). A clear trend in tendency to reconstruct observed when going from 3d Ni Cu 5d Pt Au. results are discussed together with some previous calculations other many-atom models for total energy calculation metals. undergo is found be related anisotropy surface energies on (111) (110) surfaces. By investigating two-body three-body interactions it...

We report experimental results for the behavior of slow-combustion fronts in presence a columnar defect with enhanced or reduced driving, and compare them those mean-field theory. also simulation an analogous problem driven flow particles hard-core repulsion (ASEP) single bond different hopping probability. The difference shape front profiles vs driving clearly demonstrates existence Kardar-Parisi-Zhang-type nonlinear term effective evolution equation fronts. find that display faceted form...

We present exact and asymptotic results for clusters in the one-dimensional totally asymmetric exclusion process (TASEP) with two different dynamics. The expected length of largest cluster is shown to diverge logarithmically an increasing system size ordinary TASEP dynamics as a logarithm divided by double generalized dynamics, where hopping probability particle depends on it belongs to. connection theory extreme order statistics discussed detail. also consider related model interface...

Magnetic properties of small antiferromagnetic clusters are studied within the framework nearest-neighbor Ising model. We analyze in detail several cluster geometries with different lattice structures and examine competing effects due to order, frustration, external field. For some presence an magnetic field, magnetization is found increase increasing temperature a considerable range. also consider conditions under which can display superparamagnetic behavior. In general, depend strongly on...