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Related papers: Surface segregation in nanoparticles from first pr…

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The ordered structure of binary alloy nanoparticles determines their magnetic and catalytic characteristics. In the alloys after annealing, one of the components preferentially segregates on the surface to reduce surface energy. This…

We have calculated surface energies and surface magnetic order of various low-indexed surfaces of monoatomic Fe, Co, and Pt, and binary, ordered FePt, CoPt, and MnPt using density functional theory. Our results for the binary systems…

Materials Science · Physics 2010-01-05 A. Dannenberg , M. E. Gruner , A. Hucht , P. Entel

Recent experiments showed that the robust charge-ordering in manganites can be weakened by reducing the grain size down to nanoscale. Weak ferromagnetism was evidenced in both nanoparticles and nanowires of charge-ordered manganites. To…

Materials Science · Physics 2007-05-23 S. Dong , F. Gao , Z. Q. Wang , J. -M. Liu , Z. F. Ren

The kinetics of order-disorder transition of FePt nanoparticles during high temperature annealing is theoretically investigated. A model is developed to address the influence of large surface to volume ratio of nanoparticles on both the…

Materials Science · Physics 2015-06-17 Shuaidi Zhang , Weihong Qi , Baiyun Huang

We present the results of Monte Carlo simulations of a model of a single maghemite ferrimagnetic nanoparticle including radial surface anisotropy distinct from that in the core with the aim to clarify what is its role on the magnetization…

Materials Science · Physics 2007-05-23 Oscar Iglesias , Amilcar Labarta

Within the atom-vacancy exchange mechanism in a nearest-neighbor interaction model we investigate the kinetics of surface-induced ordering processes close to the (001) surface of an fcc A_3B-alloy. After a sudden quench into the ordered…

Statistical Mechanics · Physics 2009-11-07 Michael Kessler , Wolfgang Dieterich , Andrzej Majhofer

A number of novel experimental and theoretical results have recently been obtained on active soft matter, demonstrating the various interesting universal and anomalous features of this kind of driven systems. Here we consider a fundamental…

Soft Condensed Matter · Physics 2015-06-12 Enys Mones , András Czirók , Tamás Vicsek

Ordering nanoparticles into a desired super-structure is often crucial for their technological applications. We use molecular dynamics simulations to study the assembly of nanoparticles in a polymer brush randomly grafted to a planar…

Soft Condensed Matter · Physics 2017-12-11 Shengfeng Cheng , Mark J. Stevens , Gary S. Grest

The growth of binary alloy clusters on a weakly interacting substrate through codeposition of two atomic species is studied by kinetic Monte Carlo simulation. Our model describes salient features of CoPt$_3$-nanoclusters, as obtained…

Statistical Mechanics · Physics 2007-05-23 Stefan Heinrichs , Wolfgang Dieterich , Philipp Maass

Nanopatterned FePt nano-dots often exhibit low coercivity and a broad switching field distribution, which could arise due to edge damage during the patterning process causing a reduction in the $L1_{0}$ ordering required for a high…

Materials Science · Physics 2014-11-19 Jung-Wei Liao , Unai Atxitia , Richard F. L. Evans , Roy W. Chantrell , Chih-Huang Lai

We study the finite-size and surface effects on the thermal and spatial behaviors of the magnetisation of a small magnetic particle. We consider two systems: 1) A box-shaped isotropic particle of simple cubic structure with either periodic…

Materials Science · Physics 2009-10-31 H. Kachkachi , M. Nogues , E. Tronc , D. A. Garanin

The structural and dynamical properties of FePt nanoparticles were studied within the density functional theory. The effect of size and chemical composition on dynamical stability of nanoparticles was investigated for the cuboctahedral and…

Mesoscale and Nanoscale Physics · Physics 2017-05-03 Przemysław Piekarz , Jan Łażewski , Paweł T. Jochym , Małgorzata Sternik , Krzysztof Parlinski

We present a microscopic model for nanoparticles, of the maghemite ($\gamma $% -Fe$_{2}$O$_{3}$) type, and perform classical Monte Carlo simulations of their magnetic properties. On account of M\"{o}ssbauer spectroscopy and high-field…

Materials Science · Physics 2009-10-31 H. Kachkachi , A. Ezzir , M. Nogues , E. Tronc

We study a system of hard-core particles sliding downwards on a fluctuating one-dimensional surface which is characterized by a dynamical exponent $z$. In numerical simulations, an initially random particle density is found to coarsen and…

Statistical Mechanics · Physics 2009-10-31 Dibyendu Das , Mustansir Barma

By means of density functional theory we have undertaken a structural, electronic and magnetic survey of the adsorption of the Fe_xPt_y(x,y=<4) clusters on MgO (001) surface under the generalized gradient approximation. We have tested…

Materials Science · Physics 2015-06-23 Ramon Cuadrado , Roy W. Chantrell

The segregation behavior of the bimetallic alloys PtPd and CoCr in the case of bare surfaces and in the presence of an oxygen ad-layer has been studied by means of first-principles modeling based on density-functional theory (DFT). For both…

We investigate the consequence of the dimension reduction on the magnetic anisotropy of FePt and CoPt nanoparticles. Using an extension of the magnetic anisotropy model of N\'eel, we show that, due to a statistical finite size effect,…

Mesoscale and Nanoscale Physics · Physics 2011-06-01 Stanislas Rohart , Florent Tournus , Véronique Dupuis

The thermodynamic properties of gases have been understood primarily through phase diagrams of bulk gases. However, observations of gases confined in a nanometer space have posed a challenge to the principles of classical thermodynamics.…

Soft Condensed Matter · Physics 2014-10-31 Ing-Shouh Hwang , Yi-Hsien Lu , Chih-Wen Yang , Chung-Kai Fang , Hsien-Chen Ko

The performance characteristics of magnetic nanoparticles towards application, e.g. in medicine, imaging, or as sensors, is directly determined by their magnetization relaxation and total magnetic moment. In the commonly assumed picture,…

A FePd alloy was nanostructured by severe plastic deformation following two different routes: ordered and disordered states were processed by high pressure torsion (HPT). A grain size in a range of 50 to 150 nm is obtained in both cases.…

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