Open Access. Powered by Scholars. Published by Universities.®
Physical Sciences and Mathematics Commons™
Open Access. Powered by Scholars. Published by Universities.®
Articles 1 - 9 of 9
Full-Text Articles in Physical Sciences and Mathematics
Nonextensivity In Magnetic Nanoparticle Ensembles, Christian Binek, Srinivas Polisetty, Xi He, Tathagata Mukherjee, Rajasekaran Rajesh, Jody G. Redepenning
Nonextensivity In Magnetic Nanoparticle Ensembles, Christian Binek, Srinivas Polisetty, Xi He, Tathagata Mukherjee, Rajasekaran Rajesh, Jody G. Redepenning
Department of Physics and Astronomy: Faculty Publications
A superconducting quantum interference device and Faraday rotation technique are used to study dipolar interacting nanoparticles embedded in a polystyrene matrix. Magnetization isotherms are measured for three cylindrically shaped samples of constant diameter but various heights. Detailed analysis of the isotherms supports Tsallis' conjecture of a magnetic equation of state that involves temperature and magnetic field variables scaled by the logarithm of the number of magnetic nanoparticles. This unusual scaling of thermodynamic variables, which are conventionally considered to be intensive, originates from the nonextensivity of the Gibbs free energy in three-dimensional dipolar interacting particle ensembles. Our experimental evidence for nonextensivity …
Publications David J. Sellmyer (Department Of Physics And Astronomy And Director Nebraska Center For Materials And Nanoscience - Ncmn), David J. Sellmyer
Publications David J. Sellmyer (Department Of Physics And Astronomy And Director Nebraska Center For Materials And Nanoscience - Ncmn), David J. Sellmyer
Department of Physics and Astronomy: Faculty Publications
Chronological list of 396 research articles and 45 books, chapters, and reviews. Covers the years 1995 through 2006 (August).
Temperature Dependence Of Magnetoresistance In Magnetic Tunnel Junctions With Different Free Layer Structures, L. Yuan, Sy_Hwang Liou, Dexin Wang
Temperature Dependence Of Magnetoresistance In Magnetic Tunnel Junctions With Different Free Layer Structures, L. Yuan, Sy_Hwang Liou, Dexin Wang
Department of Physics and Astronomy: Faculty Publications
The temperature and bias voltage dependence of magnetoresistance and the resistance of two types of magnetic tunnel junction (MTJ) samples were studied. These two types of MTJ samples have different free layer structures, while having the same pinned layer structures and with the same material for free and reference layers. The layer structure for type 1 MTJs is 80Ru-8CoFeB-15Al2O3-50CoFeB-9Ru-54FeCo- 350CrMnPt (in angstroms). The layer structure for type 2 MTJs is 80Ru-40CoFeB-50RuTa-40CoFeB- 15Al2O3-50CoFeB-9Ru-54FeCo-350CrMnPt. The tunneling magnetoresistance (TMR) ratio [(RAP-Rp)/Rp] is about 26% and 69% at room temperature for type 1 and type 2 MTJs, …
Comparison Of The Electronic Structure Of Two Polymers With Strong Dipole Ordering, Jie Xiao, Luis G. Rosa, Matt Poulsen, Danqin Feng, D. Sahadeva Reddy, James M. Takacs, Lei Cai, Jiandi Zhang, Stephen Ducharme, Peter A. Dowben
Comparison Of The Electronic Structure Of Two Polymers With Strong Dipole Ordering, Jie Xiao, Luis G. Rosa, Matt Poulsen, Danqin Feng, D. Sahadeva Reddy, James M. Takacs, Lei Cai, Jiandi Zhang, Stephen Ducharme, Peter A. Dowben
Department of Physics and Astronomy: Faculty Publications
Two different polymers, with large local electric dipoles, are compared: copolymers of polyvinylidene fluoride with trifluoroethylene [P(VDF-TrFE, 70%:30%)] and polymethylvinylidenecyanide (PMVC). While the different local point group symmetries play a key role, both crystalline polymers exhibit intra-molecular band structure, though the Brillouin zone critical points differ.
Exchange Bias Training Effect In Coupled All Ferromagnetic Bilayer Structures, Christian Binek, Srinivas Polisetty, Xi He, A. Berger
Exchange Bias Training Effect In Coupled All Ferromagnetic Bilayer Structures, Christian Binek, Srinivas Polisetty, Xi He, A. Berger
Department of Physics and Astronomy: Faculty Publications
Exchange coupled bilayers of soft and hard ferromagnetic thin films show remarkable analogies to conventional antiferromagnetic/ferromagnetic exchange bias heterostructures. Not only do all these ferromagnetic bilayers exhibit a tunable exchange bias effect, they also show a distinct training behavior upon cycling the soft layer through consecutive hysteresis loops. In contrast with conventional exchange bias systems, such all ferromagnetic bilayer structures allow the observation of training induced changes in the bias-setting hardmagnetic layer by means of simple magnetometry. Our experiments show unambiguously that the exchange bias training effect is driven by deviations from equilibrium in the pinning layer. A comparison of …
Electronic Structure And Vibrational Spectra Of C2B10-Based Clusters And Films, Kyungwha Park, M. R. Pederson, L. L. Boyer, Wai-Ning Mei, Renat F. Sabirianov, Xiao Cheng Zeng, Satya S. Bulusu, Seamus Curran, James Dewald, Ellen Day, Shireen Adenwalla, Manuel Diaz, Luis G. Rosa, Snjezana Balaz, Peter A. Dowben
Electronic Structure And Vibrational Spectra Of C2B10-Based Clusters And Films, Kyungwha Park, M. R. Pederson, L. L. Boyer, Wai-Ning Mei, Renat F. Sabirianov, Xiao Cheng Zeng, Satya S. Bulusu, Seamus Curran, James Dewald, Ellen Day, Shireen Adenwalla, Manuel Diaz, Luis G. Rosa, Snjezana Balaz, Peter A. Dowben
Department of Physics and Astronomy: Faculty Publications
The electronic structure, total energy, and vibrational properties of C2B10H12 (carborane)molecules and C2B10 clusters formed when the hydrogen atoms are removed from carborane molecules are studied using density functional methods and a semiempirical model. Computed vibrational spectra for carborane molecules are shown to be in close agreement with previously published measured spectra taken on carborane solids. Semiconducting boron carbide films are prepared by removing hydrogen from the three polytypes of C2B10H12 deposited on various surfaces. Results from x-ray and Raman scattering measurements on these films are reported. …
The Electronic Structure And Band Hybridization Of Co/Ti Doped Bafe12O19, Natalie Palina, H. Modrow, R. Müller, J. Hormes, Peter A. Dowben, Yaroslav B. Losovyj
The Electronic Structure And Band Hybridization Of Co/Ti Doped Bafe12O19, Natalie Palina, H. Modrow, R. Müller, J. Hormes, Peter A. Dowben, Yaroslav B. Losovyj
Department of Physics and Astronomy: Faculty Publications
We identify contributions to the valence band of the nanosized BaFe12−2xCoxTixO19 barium ferrite particles, from the cobalt and titanium dopants. Resonant photoemission results show that cobalt and titanium dopants strongly hybridize with the barium ferrite matrix. Fano resonances are identified in the valence band region, at the Ba (5s), Ti (3p) and Co (3p) thresholds, and there are significant contributions to the density of states, residing within 2 eV of the Fermi level, from barium and/or iron.
"Preface" To Advanced Magnetic Nanostructures, David J. Sellmyer, Ralph Skomski
"Preface" To Advanced Magnetic Nanostructures, David J. Sellmyer, Ralph Skomski
Department of Physics and Astronomy: Faculty Publications
A key trend in modern science and technology is the exploitation of phenomena occurring on length scales between 1 nm and 1000 nm. This nanotechnology or nanoscience approach has lead to the emergence of fi elds such as nanobiology, nanoelectronics, and nanochemistry. An important and—in many respects—pivotal area is nanomagnetism. From early precursors in the first half of the 20th century to recent developments, magnetic nanostructures are interesting scientific objects with many present and emerging applications, including permanent magnets, soft magnets, magnetic recording media, sensors, and structures and materials for spin electronics. A key advantage of artificial magnetic nanostructures is …
A Three-Grating Electron Interferometer, G. Gronniger, Brett E. Barwick, Herman Batelaan
A Three-Grating Electron Interferometer, G. Gronniger, Brett E. Barwick, Herman Batelaan
Department of Physics and Astronomy: Faculty Publications
We report the observation of fringes from a three-grating electron interferometer. Interference fringes have been observed at low energies ranging from 6 to 10 keV. Contrasts of up to 25% are recorded and exceed the maximal contrast of the classical equivalent Moiré deflectometer. This type of interferometer could serve as a separate beam Mach–Zehnder interferometer for low-energy electron interferometry experiments.