Physics Commons^™

Radiative Neutron Β-Decay In Effective Field Theory, Susan Gardner, Véronique Bernard, Chi Zhang

School of Biological Sciences: Faculty Publications

We consider radiative β-decay of the neutron in heavy baryon chiral perturbation theory. Nucleon-structure effects not encoded in the weak coupling constants g_A and g_V are determined at next-to-leading order in the chiral expansion, and enter at the O(0.5%)-level, making a sensitive test of the Dirac structure of the weak currents possible.

Specification Of Jecp/Holz, An Interactive Computer Program For Simulation Of Holz Pattern, Xingzhong Li

Nebraska Center for Materials and Nanoscience: Faculty Publications

1. Purpose of the program 2. Graphic user interface and program design 3. Formulas for calculating the positions of the HOLZ lines 4. System requirement 5. Installation and user instruction 6. How to contact the author 7. References

1. Purpose of the program JECP/HOLZ (Li, 2005a) is one computer program in the Java Electron Crystallography Package (JECP), which is designed and written by Dr. XingZhong Li. The package is developed for quantitative electron diffraction and image processing purpose, JECP/HOLZ is an interactive program for simulation of the higher-order Laue zone (HOLZ) lines using kinematical approximation and a first-order dynamic correction. …

Magnetic Moments And Adiabatic Magnetization Of Free Cobalt Clusters, Xiaoshan Xu, Shuangye Yin, Ramiro Moro, Walt A. De Heer

Xiaoshan Xu Papers

Magnetizations and magnetic moments of free cobalt clusters CoN (12< N <200) in a cryogenic (25 K ≤ T ≤ 100 K) molecular beam were determined from Stern-Gerlach deflections. All clusters preferentially deflect in the direction of the increasing field and the average magnetization resembles the Langevin function for all cluster sizes even at low temperatures. We demonstrate in the avoided crossing model that the average magnetization may result from adiabatic processes of rotating and vibrating clusters in the magnetic field and that spin relaxation is not involved. This resolves a longstanding problem in the interpretation of cluster beam deflection experiments with implications for nanomagnetic systems in …

Examining The Screening Limit Of Field Effect Devices Via The Metal-Insulator Transition, X. Hong, A. Posadas, C. H. Ahn

Xia Hong Publications

The electronic screening length, the distance over which an electric field is attenuated in a material, imposes a lower physical bound on the lateral size scaling of semiconductor field effect devices. Alternatives will be needed to achieve devices whose characteristic dimensions approach a nanometer. In this work, we demonstrate the atomic-scale nature of screening at high electron densities, using the polarization field of a ferroelectric oxide, Pb(Zr,Ti)O₃, to electrostatically modulate the metallicity of ultrathin manganite La_1−xSr_xMnO₃ (LSMO) films near the metal-insulator transition. Within the screening length, the transport characteristics of LSMO vary sharply …

Einstein’S Impact On Optics At The Frontier, Donald Umstadter

Donald Umstadter Publications

The seminal contributions made by Einstein a century ago have enabled a new frontier area of science, called high-field science. This research involves the physics of the interactions of matter with electromagnetic fields at its highest levels ever achieved in the laboratory. Besides being of fundamental importance to physics research, the discoveries being made in this area are also leading to a new generation of compact and ultrashort-duration particle accelerators and X-ray light sources, with applications ranging from nuclear fusion to cancer therapy.

Measurement Of Magnetic Moments Of Free BiNMnM Clusters, Shuangye Yin, Xiaoshan Xu, Ramiro Moro, Walt A. De Heer

Xiaoshan Xu Papers

Magnetic properties of free Bi_NMn_M clusters (N=2–20, M=0–7) are determined from Stern-Gerlach deflections at low temperature (46.5 K). Pure bismuth clusters with odd number of atoms exhibit paramagnetic deflections. The addition of manganese atoms produces a ferromagnetic response which is strongly size dependent. Certain combinations have very large magnetic moments such as Bi₅Mn₃, Bi₉ Mn₄, Bi₁₀Mn₅, and Bi₁₂Mn₆.