We report a high-pressure single crystal study of the topological superconductor Cu$_x$Bi$_2$Se$_3$. Resistivity measurements under pressure show superconductivity is depressed smoothly. At the same time the metallic behavior is gradually lost. The u
pper critical field data $B_{c2}(T)$ under pressure collapse onto a universal curve. The absence of Pauli limiting and the comparison of $B_{c2}(T)$ to a polar state function point to spin-triplet superconductivity, but an anisotropic spin-singlet state cannot be discarded completely.
The pseudogap state is one of the peculiarities of the cuprate high temperature superconductors. Here we investigate its presence in BaCo$_{x}$Fe$_{2-x}$As$_{2}$, a member of the pnictide family, with temperature dependent scanning tunneling spectros
copy. We observe that for under, optimally and overdoped systems the gap in the tunneling spectra always closes at the bulk T$_{c}$, ruling out the presence of a pseudogap state. For the underdoped case we observe superconducting gaps over large fields of view, setting a lower limit of tens of nanometers on the length scale of possible phase separated regions.
We report measurements of the coefficient of linear thermal expansion, $alpha (T)$, of the superconducting ferromagnet UCoGe. The data taken on a single-crystalline sample along the orthorhombic crystal axes reveal a pronounced anisotropy, with the l
argest length changes along the $b$ axis. The large values of the step sizes $Delta alpha$ at the magnetic and superconducting phase transitions provide solid evidence for bulk magnetism and superconductivity. Specific-heat measurements corroborate bulk superconductivity. Thermal-expansion measurements in magnetic fields $B parallel a,b$ show $Delta alpha$ at $T_C$ grows rapidly, which indicates the character of the ferromagnetic transition becomes first-order-like.
