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We report on the observation of bulk superconductivity from dc magnetization measurements in a cylindrical single crystal of Cu x Bi 2 Se 3 . The magnitude of the magnetization in the Meissner state is very small, and the magnetic-field dependence of the magnetization just above the lower critical field H c1 is very different from those of usual type-II superconductors. We studied the character of the vortex state theoretically in a spin-triplet pairing superconductor and compared it with the experimental results. The results showed that the superconductivity observed in Cu x Bi 2 Se 3 is consistent with the spin-triplet pairing superconductivity with odd parity. We also observed a rapid relaxation phenomenon of the superconducting diamagnetism.

The present study investigated the effects of a standardized methanol extract of E. longifolia Jack containing the major quassinoid constituents of 13α(21)-epoxyeurycomanone (1), eurycomanone (2), 13α,21-dihydroeurycomanone (3) and eurycomanol (4) on the epididymal spermatozoa profile of normal and Andrographis paniculata induced infertile rats. The standardized MeOH extract at doses of 50, 100 and 200 mg/kg, the EtOAc fraction (70 mg/kg), and standardized MeOH extract at 200 mg/kg co-administered with the EtOAc fraction of A. paniculata at 70 mg/kg were each given orally to male Sprague-Dawley albino rats for 48 consecutive days. The spermatozoa count, morphology, motility, plasma testosterone level and Leydig cell count of the animals were statistically analyzed by ANOVA with a post-hoc Tukey HSD test. The results showed that the sperm count of rats given the standardized MeOH extract alone at doses of 50, 100 and 200 mg/kg were increased by 78.9, 94.3 and 99.2 %, respectively when compared with that of control (p < 0.01). The low count, poor motility and abnormal morphology of the spermatozoa induced by the A. paniculata fraction were significantly reversed by the standardized MeOH extract of E. longifolia (p < 0.001). The plasma testosterone level of the rats treated with the standardized MeOH extract at 200 mg/kg was significantly increased (p < 0.01) when compared with that of the control and infertile animals. The spermatocytes in the seminiferous tubules and the Leydig cells appeared normal. Testosterone level was significantly higher in the testes (p < 0.01) than in the plasma after 30 days of oral treatment with the standardized MeOH extract. Interestingly, eurycomanone (2) alone was detected in the rat testis homogenates by HPLC-UV and confirmed by LC/MS, and may have contributed towards the improvement of sperm quality. Thus, the plant may potentially be suitable for the management of male infertility.

We have performed angle-resolved photoemission spectroscopy of Cu x Bi 2 Se 3 as a function of Cu doping (x = 0.0-0.25) to investigate the doping-induced evolution of the electronic structure. We found that the topological surface state is preserved even in the heavy-doping region (x = 0.25), indicative of the robustness of the surface state against doping and impurities. The estimated carrier concentration is far smaller than that expected from a simple intercalation picture, and saturates at x ∼ 0.1 where superconductivity emerges. This indicates that the carrier concentration responsible for superconductivity is dominated by a subtle balance between two competing processes of electron and hole doping.

We report the observation of surface superconductivity as well as positive field cooled magnetization, along with peak-effect phenomenon in ac and dc magnetization measurements in a high-purity spherical single crystal of niobium. We study how the surface superconductivity and the positive field cooled magnetization evolve over the field ͑H͒ and the temperature ͑T͒ phase space. We suggest that the observed evolution in the strength of the positive field cooled magnetization signal may be understood on the basis of the temperature dependence of the superconducting coherence length.

We present results of magnetic measurements relating to vortex phase diagram in a single crystal of FeSe 0.5 Te 0.5 which displays second magnetization peak anomaly for H c. The possible role of the crystalline anisotropy on vortex pinning is explored via magnetic torque magnetometry. We present evidence in favor of pinning related to spatial variations of the charge carrier mean free path leading to small bundle vortex pinning by randomly distributed (weak) pinning centers for both H c and H ⊥ c. This is further corroborated using magnetization data for H c in a single crystal of FeSe 0.35 Te 0.65 . Dynamical response across second magnetization peak (SMP) anomaly in FeSe 0.5 Te 0.5 has been compared with that across the well researched phenomenon of peak effect (PE) in a single crystal of CeRu 2 .

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