Transport, thermal and magnetic measurements have been carried out on (Pr1-ySmy)1-xCaxCoO3. The system exhibits a structural phase transition accompanied by the spin state change from the intermediate spin (IS) state to the low spin (LS) state with decreasing temperature T. We have constructed a T-y phase diagram for x=0.3 and T-x ones for y=0.2 and 0.3. By analyzing their magnetic susceptibilities, the number of Co ions excited to IS state (or the electron number in the eg orbitals), nIS, are roughly estimated. With increasing y or with decreasing x, nIS decreases, and the phase transition changes gradually to the (IS-LS) crossover-like one. We discuss on the possible role of the Pr atoms in realizing the transition.Comment: 13 pages, 12 figures, Submitted to J. phys. Soc. Jp

Recently, quantum dynamics and coherence in Josephson junctions (JJs) made of high Tc superconductors (HTSCs) attract much attention. The HTSCs have relatively large energy gap and higher plasma frequency compared to those of metal superconductors, which suggests their high potential for quantum electron devices. On the other hand, the HTSC JJs have a disadvantage that the pairing symmetry is d-wave, and thus the intrinsic damping effect in the dynamic due to the nodal quasiparticles is inevitable. In addition to this, the coupling effect due to the atomic scale stack structure induces complex switching. Therefore, the peculiarities in quantum dynamics of the HTSC JJs must be clarified in order to realize the HTSCs quantum electronics. Here we report our efforts to observe macroscopic quantum tunneling and quantum coherence in the HTSC JJs.