Effects of Growth Rates and Cooling Rates on Defect Generation in Melt-Grown Copper Crystals(Physics)

Single crystals of zone-refined Cu were grown from the melt at growth rates ranging from 0.1 to 29.0 mm/min and with cooling rates of the crystal after growth varying from 0.24 to 45℃/min. It was found that the growth rate had a very important effect on the generation of dislocations and their arrays, but the cooling rate of the crystal after growth had an important effect only when the crystal had been solidified at a rate of 0.1 mm/min

Coupled channel approach to strangeness S = -2 baryon-bayron interactions in Lattice QCD

The baryon-baryon interactions with strangeness S = -2 with the flavor SU(3) breaking are calculated for the first time by using the HAL QCD method extended to coupled channel system in lattice QCD. The potential matrices are extracted from the Nambu-Bethe-Salpeter wave functions obtained by the 2+1 flavor gauge configurations of CP-PACS/JLQCD Collaborations with a physical volume of 1.93 fm cubed and with m_pi/m_K = 0.96, 0.90, 0.86. The spatial structure and the quark mass dependence of the potential matrix in the baryon basis and in the SU(3) basis are investigated.Comment: 17 pages, 15 figure

Upper Critical Field of Superconducting Amorphous Alloy Zr_<85>Si_<15>

The upper critical field H_ is measured for the amorphous superconductor Zr_Si_ (T_c=2.70 K, ρ_n=270 μΩ・cm) in the wide temperature range down to 50 mK. The conventional V-H recording in sweeping magnetic field and measurements of the flux flow resistivity defined by the I-V curve at constant field are done in order to clarify the resistive transition of the superconducting mixed-to-normal state in an amorphous superconductor with extreme softness in the flux pinning interaction. The results show the strong suppression of H_ at low temperatures, which is quite different from the upward deviation from the theoretical values H_^* due to the orbital pair breaking effect in the dirty limit, reported for some amorphous alloys. Analysis with the Werthamer-Helfand-Hohenberg theory which takes into account the effects of the orbital pair breaking, spin paramagnetism and spin-orbit interaction gives 1.51≤α≤1.77 and 1.0≤λ_≤1.7, where α is the impurity parameter and λ_ the spin orbit interaction parameter. This is the first implication for the superconductivity in amorphous alloys that the spin paramagnetic effect plays an important role in determining the low temperature H_ and the spin-orbit (spin-flip) scattering enhances H_ moderately. The counterevidence is produced to the previous observation that the upward deviation anomaly (H_>H_^*) is an intrinsic property in amorphous metals with high resitivity