A5016983770- Theoretical and Computational Physics
- Magnetic properties of thin films
- Metallic Glasses and Amorphous Alloys
- Magnetic Properties of Alloys
- Magnetic Properties and Applications
- Material Dynamics and Properties
- Rare-earth and actinide compounds
- Physics of Superconductivity and Magnetism
- Complex Systems and Time Series Analysis
- X-ray Diffraction in Crystallography
- Crystallization and Solubility Studies
- Experimental and Theoretical Physics Studies
- Magnetic and transport properties of perovskites and related materials
- Sports Dynamics and Biomechanics
- Magnetic Properties and Synthesis of Ferrites
- Advanced Condensed Matter Physics
- Magneto-Optical Properties and Applications
- Iron Metabolism and Disorders
- Adventure Sports and Sensation Seeking
- Winter Sports Injuries and Performance
- Sports Performance and Training
- Advanced Chemical Physics Studies
- Characterization and Applications of Magnetic Nanoparticles
- Geomagnetism and Paleomagnetism Studies
- Surface Roughness and Optical Measurements
Kansas State University
2000-2018
University of Pennsylvania
2010
Hospital of the University of Pennsylvania
2010
World Scientific (Singapore)
1993
University of Nebraska–Lincoln
1982-1984
University of Sussex
1981-1983
Northwick Park Hospital
1973
The Royal Free Hospital
1972-1973
University College London
1972-1973
The effects of interface exchange on magnetic hysteresis are considered for a variety situations in two-phase model which the phases coupled antiferromagnetically. This work is motivated by studies Co-CoO nanophase systems where inverted loops, phenomenon closely related to shifted obtained. Some previous examples with loops reviewed and uniaxial anisotropy considered. It should be emphasized that this cannot completely explain but it does show partially can Cases H not along an axis...
S ummary . Experimentally induced acute inflammation in rats is associated with a fall plasma iron and iron‐binding capacity. Transferrin synthesis by the liver of these animals normal not increased presence low serum iron, as it deficiency. Human splenic macrophages rabbit pulmonary which were maintained culture for up to 1 week showed an ability take protein‐bound labelled proteins into cytoplasm. It suggested that macrophage may be site both sequestration transferrin degradation. This...
Although ionizing radiation induces germline mutations in animals, human studies of radiation-exposed populations have not detected an effect. We conducted a case-control study sporadic bilateral retinoblastoma, which results from new RB1 mutation, to investigate gonadal exposure parents medical sources before their child's conception. Parents 206 cases nine North American institutions and 269 controls participated; fathers 184 223 friend relative mothers 204 260 provided information...
Elemental rare-earths R (Gd, Dy, Tb) are prepared in layer and particle form to look at the effects of geometry (layers or particles) size (layer thickness diameter) on their magnetism. All rare-earth systems show a maximum coercivity (measured 4.5 K) about 10 nm (average diameter thickness). Magnetic ordering temperature is reduced significantly compared bulk when below for both geometry. Geometry has significant effect with particles tending have larger than layers.
Tb nanoscale particles are prepared in a matrix of Ti by sputtering. A range samples made with average particle diameter ranging from 1.5 to 21 nm. The magnetic transition temperature is depressed for smaller due finite size effects. coercivity at 4.5 K shows maximum 22 kOe approximately 7 nm being factor 2.4 larger than thick film Tb. We compare the our multilayers form Tb/Mo and find systems more confined geometry particles.
We have prepared homogeneous SmCox (x=5–26) sputtered thin films of thickness 500 nm with excess Co compared to SmCo5. The purpose is determine how any spring exchange incorporated by the improves energy product. Films are subjected a 30 s or 20 min anneal crystallize Sm–Co. In case both methods x-ray diffraction indicated no preferential orientation Sm–Co film after annealing. best value maximum product, BHmax, 19 MG Oe (151 kJ/m3) and found in sample x 12 at 700 °C. also compare these...
NdFeB thin films of the form A(20 nm)/NdFeB(d nm)/A(20 nm) were prepared by magnetron sputtering on a Si(100) substrate. The hard Nd2Fe14B phase is formed postanneal in vacuum. buffer layers A used are Cr, Mo, Ta, Ti, and layer thickness 540, 180, 90, 54 nm. We have found several different combinations anneal temperature, layer, film d that lead to large coercivity, as high 17.0 kOe, energy product, 10.3 MG Oe. temperature dependence coercivity was analyzed using modified Brown’s equation we...
We have prepared superconducting Bi-based compounds by sintering and find a weak diamagnetic response at 110 K strong about 80 K. The dominant structural phase was identified x-ray diffraction to be ${\mathrm{Bi}}_{2}$${\mathrm{SrCa}}_{2}$${\mathrm{Cu}}_{2}$${\mathrm{O}}_{8\mathrm{\ensuremath{-}}\mathrm{y}}$ low-field magnetization indicates that approximately 60% (by volume) of the sample is superconducting. X\ensuremath{\alpha} other calculations interpret copper binding energies satellite...
The magnetic state and anisotropy of amorphous rare-earth transition-metal systems with a microscopic random uniaxial are discussed. Both sputtered Tb-Fe rapidly quenched Gd65−xRxCo35 alloys (R is rare earth) were studied. low-temperature these depends on the anisotropy, exchange, applied field strength. For case weak (alloys small concentrations anisotropic low-field results can be explained in terms correlated spin-glass higher-field magnetization curves by ferromagnet wandering axis...
The generality and universality of the Ising spin-glass-like phase transitions observed in several rare-earth, random-anisotropy magnets are discussed. Some uncertainties practical problems determining critical exponents considered, a comparison is made to insulating spin glasses crystalline where an apparent anisotropy-induced crossover from Heisenberg Ising-like behavior seen. observation reentrant transition weak anisotropy system its correlation with theory Chudnovsky, Saslow, Serota...
The magnetic properties of amorphous alloys with composition ${\mathrm{Gd}}_{\mathrm{x}}$${\mathrm{La}}_{72\mathrm{\ensuremath{-}}\mathrm{x}}$${\mathrm{Ga}}_{18}$${\mathrm{B}}_{10}$ have been investigated using ac-susceptibilty and dc-magnetization techniques in the temperature range 4.2--300 K. This system shows double-transition behavior for x\ensuremath{\gtrsim}67 paramagnetic--spin-glass transition x67. Time-dependent magnetization effects are present spin-glass phase these vanish finite...
The effect of hydrogen on magnetic properties metallic glasses the form (R80Ga20)1−xTxHy where R=Pr, Nd, Gd, Tb, Er; T=Cr, Fe, Co, B; 0≤x≤0.3 and 0≤y≤1.7 is reported. anisotropic rare earth without H all exhibit speromagnetic (spin-glass-like) transitions hydrogen, in most cases, to lower peak χac significantly but leave TC relatively unchanged. For Gd glass with T=Fe x=0.1 introduction at level y=0.55 causes a large decrease significant increase local random anisotropy. Models for these...
We report on finite size effects and evidence for quantum mesoscopic tunneling (QMT) in thin isolated rare-earth layers prepared the form of R/Mo multilayers where R represents Tb, Dy, or Dy50Co50. The magnetic transition temperature Tc decreases with decreasing layer thickness is discussed within a scaling theory. Evidence QMT found relaxation measurements these systems sharp crossover to temperature-independent regime at low temperatures. Tb system has T0 20 K, largest value reported so...
We have studied the effect of anisotropy on transition behavior in Gd-transition-metal glasses. Anisotropy is induced a controlled fashion by formation alloys with anisotropic rare-earth metals. For large we find paramagnetic-speromagnetic as seen many other workers. In speromagnetic state spins are frozen random direction much like spin-glass state. small enough see double-transition that sequence paramagnetic-to-ferromagnetic-to-speromagnetic transitions decreasing temperature. This...
We report studies of the magnetic critical behavior as a function anisotropy strength in rare-earth-rich glasses. Anisotropy is induced Gd-Co by alloying with Tb. The system studied Gd65−xTbxCo35 and random (RMA) may be increased increasing x. x=0 alloy this series has been shown to exhibit standard expected for second-order phase transition. With x we find deviations from due presence RMA. present detailed results composition x=50 at. % show that large enough fields continues ferromagnetic...