Temperature dependence of the spin and orbital magnetization density in Sm1−xGdxAl2Sm_{1-x}Gd_{x} Al_{2} around the spin-orbital compensation point

Non-resonant ferromagnetic x-ray diffraction has been used to separate the spin and orbital contribution to the magnetization density of the proposed zero-moment ferromagnet $Sm_{0.982}Gd_{0.018} Al_{2}$. The alignment of the spin and orbital moments relative to the net magnetization shows a sign reversal at 84K, the compensation temperature. Below this temperature the orbital moment is larger than the spin moment, and vice versa above it. This result implies that the compensation mechanism is driven by the different temperature dependencies of the $4f$ spin and orbital moments. Specific heat data indicate that the system remains ferromagnetically ordered throughout

Crack initiation at notches in low cycle fatigue Final report, 1 Aug. 1968 - 15 Mar. 1969

Crack initiation at notches in low cycle fatigue determined by plastic strain distributio

Anisotropic Diamagnetic Response in Type-II Superconductors with Gap and Fermi-Surface Anisotropies

Effects of anisotropic gap structures on a diamagnetic response are investigated in order to demonstrate that the field-angle-resolved magnetization ($M_L(\chi)$) measurement can be used as a spectroscopic method to detect gap structures. Our microscopic calculation based on the quasiclassical Eilenberger formalism reveals that $M_L(\chi)$ in a superconductor with four-fold gap displays a four-fold oscillation reflecting the gap and Fermi surface anisotropies, and the sign of this oscillation changes at a field between $H_{c1}$ and $H_{c2}$. As a prototype of unconventional superconductors, magnetization data for borocarbides are also discussed.Comment: 5 pages, 4 figure

Oxygen vacancy segregation and space-charge effects in grain boundaries of dry and hydrated BaZrO3

A space-charge model is applied to describe the equilibrium effects of segregation of double-donor oxygen vacancies to grain boundaries in dry and wet acceptor-doped samples of the perovskite oxide BaZrO3. The grain boundary core vacancy concentrations and electrostatic potential barriers resulting from different vacancy segregation energies are evaluated. Density-functional calculations on vacancy segregation to the mirror-symmetric \Sigma 3 (112) [-110] tilt grain boundary are also presented. Our results indicate that oxygen vacancy segregation can be responsible for the low grain boundary proton conductivity in BaZrO3 reported in the literature

Single-crystal growth of underdoped Bi-2223

To investigate the origin of the enhanced Tc ({\approx} 110 K) of the trilayer cuprate superconductor Bi2Sr2Ca2Cu3O10+{\delta} (Bi-2223), its underdoped single crystals are a critical requirement. Here, we demonstrate the first successful in-plane resistivity measurements of heavily underdoped Bi-2223 (zero-resistivity temperatures {\approx} 20~35 K). Detailed crystal growth methods, the annealing process, as well as X-ray diffraction (XRD) and magnetic susceptibility measurement results are also reported.Comment: 4 pages, 4 figures, 27th International Symposium on Superconductivity, ISS 2014, to appear in Physics Procedi

S-wave bottom tetraquarks

The relativistic four-quark equations are found in the framework of coupled-channel formalism. The dynamical mixing of the meson-meson states with the four-quark states is considered. The four-quark amplitudes of the tetraquarks, including $u$, $d$, $s$ and bottom quarks, are constructed. The poles of these amplitudes determine the masses and widths of $S$-wave bottom tetraquarks.Comment: 8 pages, late

Development of a Large-Area Aerogel Cherenkov Counter Onboard BESS

This paper describes the development of a threshold type aerogel Cherenkov counter with a large sensitive area of 0.6 m$^2$ to be carried onboard the BESS rigidity spectrometer to detect cosmic-ray antiprotons. The design incorporates a large diffusion box containing 46 finemesh photomultipliers, with special attention being paid to achieving good performance under a magnetic field and providing sufficient endurance while minimizing material usage. The refractive index of the aerogel was chosen to be 1.03. By utilizing the muons and protons accumulated during the cosmic-ray measurements at sea level, a rejection factor of 10$^4$ was obtained against muons with $\beta \approx 1$, while keeping 97% efficiency for protons below the threshold.Comment: 13 pages, LaTex, 9 eps figures included, submitted to NIM