Carrier concentration dependence and impurity effects of microwave response in Bi2Sr2CaCu2O8+ y

We report the surface impedance (Z _s ) measurements in high quality single crystals of Bi₂Sr₂CaCu₂O_8+y . At relatively low oxygen content, the change of the penetration depth, Δλ(T) ≡λ(T)-λ(0), of the pure single crystals exhibits linear temperature dependence both parallel to the CuO₂ planes and in thec direction. In contrast to this behavior, by further oxygenation or 0.6% Zn substitution, theT-linear dependence is disrupted andT ² dependence of Δλ is observed. We also found that 0.9% Ni-substitution induces no pairbreaking effect. The present results suggest that the low-lying excitation spectrum of quasiparticles depends on the carrier concentration and is easily changed by a small amount of Zn substitution.     

Elasto-plastic phase-field simulation of martensitic transformation in lath martensite steels

Phase-field simulation of lath martensite formation in Fe–0.1C mass% steel was carried out based on the two types of slip deformation (TTSD) model, which is recently developed as a result of analytical solution for the martensitic transformation being composed of Bain deformation and plastic deformation but without lattice rotation matrix. The simulation results reveal that the plastic deformation along the two types of slip system is complementary. The simulation result of the relationship between the two types of slip deformation is consistent with the analytical result calculated by TTSD model, indicating the validity of TTSD model for explaining the formation of lath martensite.