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Full-Text Articles in Physical Sciences and Mathematics
Ion Clustering In Aqueous Salt Solutions Near The Liquid/Vapor Interface, Smith J. D., Steven W. Rick
Ion Clustering In Aqueous Salt Solutions Near The Liquid/Vapor Interface, Smith J. D., Steven W. Rick
Chemistry Faculty Publications
Molecular dynamics simulations of aqueous NaCl, KCl, NaI, and KI solutions are used to study the effects of salts on the properties of the liquid/vapor interface. The simulations use the models which include both charge transfer and polarization effects. Pairing and the formation of larger ion clusters occurs both in the bulk and surface region, with a decreased tendency to form larger clusters near the interface. An analysis of the roughness of the surface reveals that the chloride salts, which have less tendency to be near the surface, have a roughness that is less than pure water, while the iodide …
Towards One Key To One Lock: Catalyst Modified Indium Oxide Nanoparticle Thin Film Sensor Array For Selective Gas Detection, Kun Yao, Daniela Caruntu, Sarah Wozny, Rong Huang, Yumi H. Ikuhara, Baobao Cao, Charles J. O'Connor, Weilie Zhou
Towards One Key To One Lock: Catalyst Modified Indium Oxide Nanoparticle Thin Film Sensor Array For Selective Gas Detection, Kun Yao, Daniela Caruntu, Sarah Wozny, Rong Huang, Yumi H. Ikuhara, Baobao Cao, Charles J. O'Connor, Weilie Zhou
Advanced Materials Research Institute (AMRI)
Homogeneous In2O3 nanoparticles (NPs) were self-assembled into thin film sensor arrays on a single chip, with further surface modification by noble metal catalysts. The NP film sensor arrays show clear current responses when exposed to different target gases, and both sensitivity and selectivity were greatly improved. Particularly, the sensors modified with Au, Pd, and Pt nanocatalysts demonstrated higher sensitivity to H2S, H-2 and CO, respectively, making the gas discrimination direct and simple, like "one key to one lock". The particle size dependence of the noble metal modifiers to the sensitivity was further investigated by tuning the sputtering parameters. Three different …
One-Pot Synthesis In Polyamines For Preparation Of Water-Soluble Magnetite Nanoparticles With Amine Surface Reactivity, Haiou Qu, Hui Ma, Aurélien Riviere, Weilie Zhou, Charles J. O'Connor
One-Pot Synthesis In Polyamines For Preparation Of Water-Soluble Magnetite Nanoparticles With Amine Surface Reactivity, Haiou Qu, Hui Ma, Aurélien Riviere, Weilie Zhou, Charles J. O'Connor
Chemistry Faculty Publications
Magnetite nanoparticles with hydrophilic surface coating are prepared in polyamine solvents. The resulting products are highly stable in polar solvent. The surface amine groups are available for secondary reactions.
Magnetoelectric Effect In Ain/Cofe Bi-Layer Thin Film Composites, S Narendra Babu, Seong-Gi Min, Amin Yourdkhani, Gabriel Caruntu, Leszek M. Malkinski
Magnetoelectric Effect In Ain/Cofe Bi-Layer Thin Film Composites, S Narendra Babu, Seong-Gi Min, Amin Yourdkhani, Gabriel Caruntu, Leszek M. Malkinski
Chemistry Faculty Publications
The present work is aimed at fabricating bi-layer aluminum nitride (AlN)/cobalt iron (CoFe) magnetoelectric (ME) thin films using reactive rf/dc magnetron sputtering. A systematic study on structural, morphological, piezoelectric, magnetic and magnetoelectric properties is undertaken. Except for AlN and CoFe, no other phases were detected with the layer thicknesses measured at160 and 130 nm, respectively. The rms roughness measured was around 2.096 nm for AlN and 1.806 nm for CoFe. The bi-layer thin film exhibited both good piezoelectricity and ferromagnetism, as well as ME effect. A 52% change observed in the piezoelectric signal, measured using magnetic field assisted piezoresponse force …
Dynamics And Collective State Of Ordered Magnetic Nanoparticles In Mesoporous Systems, Jose M. Vargas, Abhishek Srivastava, Ezra Garza, Gabriel Caruntu, Amin Yourdkhani, Leonard Spinu
Dynamics And Collective State Of Ordered Magnetic Nanoparticles In Mesoporous Systems, Jose M. Vargas, Abhishek Srivastava, Ezra Garza, Gabriel Caruntu, Amin Yourdkhani, Leonard Spinu
Chemistry Faculty Publications
In this paper we present a study of superparamagnetic and superspin glass states of magnetic nanoparticles confined in mesoporous templates. Characterization utilizes dynamic magnetization techniques, ac susceptibility, and ferromagnetic resonance, in addition to dc magnetization curves. In order to differentiate between the intrinsic and collective properties, we considered three magnetic nanoparticles systems with comparable size, shape, and crystallinity but with different intrinsic magnetocrystalline anisotropy. Further, confinement effects were studied by considering three different geometries of nanoparticles. The effect of the geometrical confinement and intrinsic anisotropy of the nanoparticles are discussed based on known theoretical predictions.
Synthesis And Piezoelectric Response Of Cubic And Spherical Linbo3 Nanocrystals, Debasish Mohanty, Girija S. Chaubey, Amin Yourdkhani, Shiva Adireddy, Gabriel Caruntu, John B. Wiley
Synthesis And Piezoelectric Response Of Cubic And Spherical Linbo3 Nanocrystals, Debasish Mohanty, Girija S. Chaubey, Amin Yourdkhani, Shiva Adireddy, Gabriel Caruntu, John B. Wiley
Chemistry Faculty Publications
Methods have been developed for the shape-selective synthesis of ferroelectric LiNbO3 nanoparticles. Decomposition of the single-source precursor, LiNb(O-Et)6, in the absence of surfactants, can reproducibly lead to either cube- or sphere-like nanoparticles. X-Ray diffraction shows that the LiNbO3 nanoparticles are rhombohedral (R3c). Sample properties were examined by piezoresponse force microscopy (PFM) and Raman where both sets of nanoparticles exhibit ferroelectricity. The longitudinal piezoelectric coefficients, d33, varied with shape where the largest value was exhibited in the nanocubes (17 pm V21 for the cubes versus 12 pm V21 for spheres).
Dynamics And Collective State Of Ordered Magnetic Nanoparticles In Mesoporous Systems, Jose M. Vargas, Abhishek Srivastava, Ezra Garza, Amin Yourdkhani, Gabriel Caruntu, Leonard Spinu
Dynamics And Collective State Of Ordered Magnetic Nanoparticles In Mesoporous Systems, Jose M. Vargas, Abhishek Srivastava, Ezra Garza, Amin Yourdkhani, Gabriel Caruntu, Leonard Spinu
Chemistry Faculty Publications
In this paper we present a study of superparamagnetic and superspin glass states of magnetic nanoparticles confined in mesoporous templates. Characterization utilizes dynamic magnetization techniques, ac susceptibility, and ferromagnetic resonance, in addition to dc magnetization curves. In order to differentiate between the intrinsic and collective properties, we considered three magnetic nanoparticles systems with comparable size, shape, and crystallinity but with different intrinsic magnetocrystalline anisotropy. Further, confinement effects were studied by considering three different geometries of nanoparticles. The effect of the geometrical confinement and intrinsic anisotropy of the nanoparticles are discussed based on known theoretical predictions.
Tuning The Thermal Relaxation Of Transition-Metal Ferrite Nanoparticles Through Their Intrinsic Magnetocrystalline Anisotropy, Jose M. Vargas, Abhishek Srivastava, Amin Yourdkhani, Luis Zaldivar, Gabriel Caruntu, Leonard Spinu
Tuning The Thermal Relaxation Of Transition-Metal Ferrite Nanoparticles Through Their Intrinsic Magnetocrystalline Anisotropy, Jose M. Vargas, Abhishek Srivastava, Amin Yourdkhani, Luis Zaldivar, Gabriel Caruntu, Leonard Spinu
Chemistry Faculty Publications
Monodispersed ferrite nanoparticles of Fe3O4, MnFe2O4, and CoFe2O4 (near to 10 nm), were synthesized by organometallic synthesis, showing the same homogeneous chemical, morphological, and crystalline characteristics. The study and correlation of the thermal relaxation processes were analyzed through static and dynamic measurements. Due to the intrinsic chemical characteristics and magnetocrystalline anisotropy of the ferrite nanoparticles, the energy barrier can be tuned to a range between 1100 K EB 7300 K, showing an alternative approach for tuning the magnetic dynamic properties, in contrast to the well-known mechanism through particle-size-effects. Specific loss power efficiencies were evaluated for the three ferrite samples. Comparing …
Highly Ordered Transition Metal Ferrite Nanotube Arrays Synthesized By Template-Assisted Liquid Phase Deposition, Amin Yourdkhani, Gabriel Caruntu
Highly Ordered Transition Metal Ferrite Nanotube Arrays Synthesized By Template-Assisted Liquid Phase Deposition, Amin Yourdkhani, Gabriel Caruntu
Chemistry Faculty Publications
Highly ordered spinel ferriteMxFe3_xO4 (M ¼ Ni, Co, Zn) nanotube arrays were synthesized in anodic aluminium oxide (AAO) templates with a pore size of 200 nm by combining a liquid phase deposition (LPD) method with a template-assisted route. The morphology of the transition metal ferrite nanotubes was characterized by electron microscopy (FE-SEM; TEM, SAED and HRTEM) and atomic force microscopy (AFM), whereas their chemical composition was determined by inductive coupling plasma (ICP). The phase purity was studied by X-ray diffraction (XRD) and the magnetic properties of the nanotubes were measured by SQUID measurements. Unlike the deposition of thin film structures, …
Proton Disorder And The Dielectric Constant Of Type Ii Clathrate Hydrates, Steven W. Rick
Proton Disorder And The Dielectric Constant Of Type Ii Clathrate Hydrates, Steven W. Rick
Chemistry Faculty Publications
Computational studies are presented examining the degree of proton disorder in argon and molecular hydrogen sII clathrate hydrates. Results are presented using a variety of model potentials for the dielectric constant, the proton order parameter, and the molecular volume for the clathrate systems. The dielectric constant for the clathrate systems is found to be lower than the dielectric constant of ice in all models. The ratio of the clathrate to ice dielectric constant correlates well with the ratio of the densities, which is not the case for comparisons to the liquid, so that differences in the dielectric constants between ice …
Improving Replica Exchange Using Driven Scaling, Steven W. Rick
Improving Replica Exchange Using Driven Scaling, Steven W. Rick
Chemistry Faculty Publications
Replica exchange is a powerful simulation method in which simulations are run at a series of temperatures, with the highest temperature chosen so phase space can be sampled efficiently. In order for swaps to be accepted, the energy distributions of adjacent replicas must have some overlap. This can create the need for many replicas for large systems. In this paper, we present a new method in which the potential energy is scaled by a parameter, which has an explicit time dependence. Scaling the potential energy broadens the distribution of energy and reduces the number of replicas necessary to span a …
High-Definition Self-Assemblies Driven By The Hydrophobic Effect: Synthesis And Properties Of A Supramolecular Nanocapsule, Bruce C. Gibb
High-Definition Self-Assemblies Driven By The Hydrophobic Effect: Synthesis And Properties Of A Supramolecular Nanocapsule, Bruce C. Gibb
Chemistry Faculty Publications
High definition self-assemblies, those that possess order at the molecular level, are most commonly made from subunits possessing metals and metal coordination sites, or groups capable of partaking in hydrogen bonding. In other words, enthalpy is the driving force behind the free energy of assembly. The hydrophobic effect engenders the possibility of (nominally) relying not on enthalpy but entropy to drive assembly. Towards this idea, we describe how template molecules can trigger the dimerization of a cavitand in aqueous solution, and in doing so are encapsulated within the resulting capsule. Although not held together by (enthalpically) strong and directional non-covalent …
Fabrication Of Magnetic Porous Hollow Silica Drug Carriers, Charles J. O'Connor, Gabriel Caruntu
Fabrication Of Magnetic Porous Hollow Silica Drug Carriers, Charles J. O'Connor, Gabriel Caruntu
Chemistry Faculty Publications
Magnetic porous hollow silica nanosphere is a new class of structured nanomaterials for drug delivery. In this paper, we report a synthesis of magnetic porous hollow silica nanospheres MPHSNs using CaCO3 /Fe3O4 composite nanoparticles and cationic surfactant double templates. Fe3O4 nanoparticles were first mixed into CaCO3 using rotating packed bed forming CaCO3 /Fe3O4 composite nanoparticles. Tetraethoxysilane was then added as precursor to form silica layer on the surface of CaCO3 /Fe3O4 composite nanoparticles, while hexadecyltrimethylammonium bromide was used as a second template to direct the formation of porous silica shells. After the calcination of the surfactants and etching away CaCO3, …
Magnetic Properties Of Variable-Sized Fe3o4 Nanoparticles Synthesized From Non-Aqueous Homogeneous Solutions Of Polyols, D. Caruntu, Gabriel Caruntu, Charles J. O'Connor
Magnetic Properties Of Variable-Sized Fe3o4 Nanoparticles Synthesized From Non-Aqueous Homogeneous Solutions Of Polyols, D. Caruntu, Gabriel Caruntu, Charles J. O'Connor
Chemistry Faculty Publications
The magnetic behaviour of well-dispersed monodisperse Fe3O4 nanoparticles with sizes varying between 6.6 and 17.8 nm prepared in a non-aqueous medium was investigated. The smaller nanocrystals exhibit superparamagnetism with the blocking temperatures increasing with the particle size, whereas the biggest particles are ferromagnetic at room temperature. The saturation magnetization values are slightly smaller than that of the bulk material, suggesting the existence of a disordered spin configuration on their surface. The thickness of the magnetically inert shell was estimated from the size variation of the magnetization at 1.9 Å. The dipole–dipole interactions between the particles were tuned by changing the …
Replica Exchange With Dynamical Scaling, Steven W. Rick
Replica Exchange With Dynamical Scaling, Steven W. Rick
Chemistry Faculty Publications
A replica exchange method is presented which requires fewer replicas and is designed to be used for large systems. In this method, dynamically scaled replicas are placed between conventional replicas at broadly spaced temperatures. The potential of the scaled replicas is linearly scaled by a dynamicalvariable which varies between 0 and 1. When the variable is near either end point the replica can undergo exchanges with one of its neighboring replicas. Two different versions of the method are presented for a model system of a small peptide in water. The scaled replica can replace manyreplicas and the method can be …
Annealing Effects On The Crystallite Size And Dielectric Properties Of Ultrafine Ba1-Xsrxtio3 (0 < X < 1) Powders Synthesized Through An Oxalate-Complex Precursor, Gabriel Caruntu, Charles J. O'Connor
Annealing Effects On The Crystallite Size And Dielectric Properties Of Ultrafine Ba1-Xsrxtio3 (0 < X < 1) Powders Synthesized Through An Oxalate-Complex Precursor, Gabriel Caruntu, Charles J. O'Connor
Chemistry Faculty Publications
Nanocrystalline Ba12xSrxTiO3 (0 , x , 1) nanopowders were prepared through the oxalate route and the influence of the thermal history on their dielectric properties was investigated. For pelletized samples obtained by decomposing the corresponding oxalate intermediates at 600 uC and then annealed at different temperatures ranging from 600 to 1000 uC the dielectric constant decreases upon increasing the strontium content of the samples. Similar behavior was observed with decreasing the temperature of the thermal treatment of the pellets, a trend which is presumably ascribed to a synergic effect of decreasing the porosity of the samples, the increase of the …
Preparation, Structural Characterization, And Dynamic Properties Investigation Of Permalloy Antidot Arrays, Scott Whittenburg, Charles J. O'Connor
Preparation, Structural Characterization, And Dynamic Properties Investigation Of Permalloy Antidot Arrays, Scott Whittenburg, Charles J. O'Connor
Chemistry Faculty Publications
Regular nanosized structures are considered to be promising materials for magnetic information storage media with high density of information. Recently attention was paid to static and dynamic magnetic properties arising from dimensional confinement in such nanostructures. Here we present an investigation of permalloy antidot arrays of different thicknesses. Thin permalloy films of thickness ranging from 10 to 500 nm were deposited on anoporous Al2O3 membranes with a pore size of 100 nm. It was found that additional ferromagnetic resonance peaks appear for film thicknesses below 100 nm, while films with larger thicknesses show resonance properties similar to continuous films. A …
Simulations Of Proton Order And Disorder In Ice Ih, Steven W. Rick
Simulations Of Proton Order And Disorder In Ice Ih, Steven W. Rick
Chemistry Faculty Publications
Computer simulations of ice Ih with different proton orientations are presented. Simulations of proton disordered ice are carried out using a Monte Carlo method which samples over proton degree of freedom, allowing for the calculation of the dielectric constant and for the examination of the degree of proton disorder. Simulations are also presented for two proton ordered structures of ice Ih, the ferroelectric Cmc21 structure or ice XI and the antiferroelectric Pna21 structure. These simulations indicate that a transition to a proton ordered phase occurs at low temperatures (below 80 K). The …
Magnetic Characterization Of Nanocrystalline Nickel Ferrite Films Processed By A Spin-Spraying Method, Gabriel Caruntu, I Dumitru, Bush Gg, Daniela Caruntu, Charles J. O'Connor
Magnetic Characterization Of Nanocrystalline Nickel Ferrite Films Processed By A Spin-Spraying Method, Gabriel Caruntu, I Dumitru, Bush Gg, Daniela Caruntu, Charles J. O'Connor
Chemistry Faculty Publications
Highly crystalline nickel ferrite films with different chemical compositions were processed via the spin-spraying method and their morphological, structural and magnetic properties were subsequently investigated. Regardless of the chemical composition, films with variable thicknesses are constructed by 200–400 nm spherical grains grown in the direction normal to the substrate surface. Magnetization measurements show that the spinel ferrite films present a hysteretic behaviour at room temperature with a randomly oriented in-plane easy axis and an anisotropy constant K1 ≈ −2.5 × 104 erg cm−3 Furthermore, the absence of an angular dependence of the coercivity for the in-plane measurement of …
Assessment Of Rarity Of The Blackmouth Shiner Notropis Melanostomus (Cyprinidae) Based On Museum And Recent Survey Data, Martin O'Connell
Assessment Of Rarity Of The Blackmouth Shiner Notropis Melanostomus (Cyprinidae) Based On Museum And Recent Survey Data, Martin O'Connell
Earth and Environmental Sciences Faculty Publications
Accurate knowledge of an organism's distribution is necessary for conserving species with small or isolated populations. A perceived rarity may only reflect inadequate sampling effort and suggest the need for more research. We used a recently developed method to evaluate the distribution of a rare fish species, the blackmouth shiner Notropis melanostomus Bortone 1989 (Cyprinidae), which occurs in disjunct populations in Mississippi and Florida. Until 1995, N. melanostomus had been collected from only three localities in Mississippi, but in 1995, eight new localities were discovered. We analyzed museum records of fish collections from Mississippi, Florida, and Alabama to compare sampling …
Synthesis And Characterization Of Nanocrystalline Zinc Ferrite, Gabriel Caruntu, Charles J. O'Connor
Synthesis And Characterization Of Nanocrystalline Zinc Ferrite, Gabriel Caruntu, Charles J. O'Connor
Chemistry Faculty Publications
We report on the synthesis of highly uniform, single phase zinc ferrite films prepared through a single step low temperature reaction by the liquid phase deposition (LPD) method. X-ray diffraction, TGA and EDX
measurements support the assumption that the as-deposited films are constituted from a mixture of crystallized FeOOH and amorphous Zn(OH)2. Upon heat treatment in air at 600 uC for one hour the intermediates are subsequently converted into the corresponding zinc ferrites. The films with adjustable chemical compositions are identified as having a spinel-type crystal structure and present a spherical or rod-like microstructure, depending on the Zn content. The …
Novel Chromium(Vi) Catalyzed Oxidation Of N-Alkylamides To Imides With Periodic Acid, Mark L. Trudell
Novel Chromium(Vi) Catalyzed Oxidation Of N-Alkylamides To Imides With Periodic Acid, Mark L. Trudell
Chemistry Faculty Publications
A novel and practical procedure for preparation of imides is described using chromium(VI) oxide to catalyze the oxidation of N-alkylamides with periodic acid in the presence of acetic anhydride in acetonitrile.
Thickness Dependence Of Magneto-Transport In Cu-Co Granular Thin Films, Scott Whittenburg
Thickness Dependence Of Magneto-Transport In Cu-Co Granular Thin Films, Scott Whittenburg
Chemistry Faculty Publications
This work explores the thickness dependence of magneto-transport properties in Cu80Co20 granular thin films with different thickness. These results are compared with silver-based film series studied earlier. It was observed that the thickness dependence of the GMR effect was sensitive to the surface chemistry of the films. The extraordinary Hall effect (EHE) in these films was measured and found to be different from the Ag-based system. In the Cu-based system, the EHE is a weak function of film thickness over the range studied. When the variation of the spontaneous magnetization is taken into account the effective EHE has a universal …
A Reoptimization Of The Five-Site Water Potential (Tip5p) For Use With Ewald Sums, Steven W. Rick
A Reoptimization Of The Five-Site Water Potential (Tip5p) For Use With Ewald Sums, Steven W. Rick
Chemistry Faculty Publications
The five-site transferable interaction potential (TIP5P) for water [M. W. Mahoney and W. L. Jorgensen, J. Chem. Phys. 112, 8910 (2000)] is most accurate at reproducing experimental data when used with a simple spherical cutoff for the long-ranged electrostatic interactions. When used with other methods for treating long-ranged interactions, the model is considerably less accurate. With small modifications, a new TIP5P-like potential can be made which is very accurate for liquid water when used with Ewald sums, a more physical and increasingly more commonly used method for treating long-ranged electrostatic interactions. The new model demonstrates a density maximum near 4 …
New Magnetic Materials Obtained By Ion-Exchange Reactions From Non-Magnetic Layered Perovskites, H Kageyama, L Viciu, Gabriel Caruntu, Y Ueda, John B. Wiley
New Magnetic Materials Obtained By Ion-Exchange Reactions From Non-Magnetic Layered Perovskites, H Kageyama, L Viciu, Gabriel Caruntu, Y Ueda, John B. Wiley
Chemistry Faculty Publications
New layered magnetic materials, (MCl)Ca2Ta3O10 (M = Cu, Fe), have been prepared by ion-exchange reactions of non-magnetic perovskite derivatives, ACa2Ta3O10 (A = Rb, Li), in corresponding anhydrous molten salts. Powder x-ray diffraction patterns of the products are successfully indexed assuming tetragonal symmetry with cell dimensions a = 3.829 Å and c = 15.533 Å for Cu, and a = 3.822 Å and c = 15.672 Å for Fe. Being separated by the Ca2Ta3O10 triple-layer perovskite slabs, the transition-metal chloride (MCl) network provides a two-dimensional magnetic lattice. Magnetic susceptibility measurements …
Magnetic Storage Device Using Induced Magnetic Reversal Of A Cobalt, Scott Whittenburg
Magnetic Storage Device Using Induced Magnetic Reversal Of A Cobalt, Scott Whittenburg
Chemistry Faculty Publications
The effects of the applied field, cell size, and cutting area on the ‘‘seed’’ induced magnetic reversal of a cobalt element array have been studied by a stochastic dynamic micromagnetics code using the Laudau–Lifshitz–Gilbert equation. Three magnetic reversal mechanisms under different magnitudes of the applied field have been investigated by examining the energy profiles. To minimize the effect of the thermal fluctuations on the switching time, an applied field with magnitude around 0.7 or 0.8 T and an element array with cutting area less than 10 nm310 nm are required. By using the smaller cellsize, the switching time and the …
Thickness Dependence Of Magnetic Blocking In Granular Thin Films, Scott Whittenburg
Thickness Dependence Of Magnetic Blocking In Granular Thin Films, Scott Whittenburg
Chemistry Faculty Publications
Interparticle interaction among single domain nanosize magnetic particles embedded in nonmagnetic matrix was studied. Attention was paid to concentrated Cu–Co granular thin films with a fixed magnetic volume fraction 20%. By analyzing theoretical models and comparing with experimental results, a dimensional constraint on the magnetic properties was found. As the film thickness reduces toward the thin limit the interparticle interaction plays important roles in modifying the magnetic behavior. The dipolar interaction energy was calculated among magnetic particles including far-neighbor interaction for films with different thickness values. When magnetization variation is included in the calculation, the resulting calculated interaction energy versus …
Dielectric Constant And Proton Order And Disorder In Ice Ih: Monte Carlo Computer Simulations, Steven W. Rick
Dielectric Constant And Proton Order And Disorder In Ice Ih: Monte Carlo Computer Simulations, Steven W. Rick
Chemistry Faculty Publications
The dielectric properties of ice Ih are studied using a Monte Carlo algorithm for sampling over proton configurations. The algorithm makes possible the calculation of the dielectric constant and other properties of the proton-disordered crystal. Results are presented for three classical models of water, two commonly used nonpolarizable models (SPC/E and TIP4P) and a polarizable model
(TIP4P-FQ).
Monte Carlo Simulation On The Indirect Exchange Interactions Of Co-Doped Zno Film, Scott Whittenburg
Monte Carlo Simulation On The Indirect Exchange Interactions Of Co-Doped Zno Film, Scott Whittenburg
Chemistry Faculty Publications
Monte Carlo simulations using a three-dimensional lattice model studied the Ruderman–Kittel–Kasuya–Yosida (RKKY) indirect exchange interaction of doped magnetic Co ions in ZnO films. The results of the calculations show that the RKKY interaction in Co-doped ZnO is long ranged and its magnitude is proportional to R−1 (inverse of the distance R from a central Co2+ ion). The sign oscillates with a frequency that depends on the concentration of the carrier. The long-distance sum of the RKKY indirect exchange energies is positive indicating that these materials are ferromagnetic, in direct correlation with previously reported results
Magnetization Reversal Of Elliptical Co/Cu/Co Pseudo-Spin Valve Dots, Scott Whittenburg
Magnetization Reversal Of Elliptical Co/Cu/Co Pseudo-Spin Valve Dots, Scott Whittenburg
Chemistry Faculty Publications
We present our recent simulated results on Cr (5 nm)/ Cu (5 nm)/ Co (5 nm)/ Cu (3 nm)/ Co (2 nm) pseudo-spin valve dots. The simulated results agree qualitatively with the experimental results. Three different sizes of elliptical dots, 150 nm3105 nm, 175 nm370 nm, and 200 nm360 nm, were simulated. Our simulations show that in these types of dots magnetization reversal occurs by the formation of domain walls: 90° for 175 nm370 nm and 360° for 200 nm360 nm. No domain wall was observed in the reversal of the 150 nm3105 nm dots. For such dots, the simulated …