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Divalent Eu (4f;{7}, J=7/2) possesses a strong local magnetic moment which suppresses superconductivity. Under sufficient pressure it is anticipated that Eu will become trivalent (4f;{6}, J=0) and a weak Van Vleck paramagnet, thus opening the door for a possible superconducting state, in analogy with Am metal (5f;{6}, J=0) which superconducts at 0.79 K. We present ac susceptibility and electrical resistivity measurements on Eu metal for temperatures 1.5-297 K to pressures as high as 142 GPa. At approximately 80 GPa Eu becomes superconducting at T_{c} approximately 1.8 K; T_{c} increases linearly with pressure to 2.75 K at 142 GPa. Eu metal thus becomes the 53rd known elemental superconductor in the periodic table.

In those cases where charge-stripe order has been observed in cuprates, the crystal structure is such that the average rotational symmetry of the CuO2 planes is reduced from fourfold to twofold. As a result, one could argue that the reduced lattice symmetry is essential to the existence of stripe order. We use pressure to restore the average fourfold symmetry in a single crystal of La1.875Ba0.125CuO4, and show by x-ray diffraction that charge-stripe order still occurs. Thus, electronically driven stripe order can spontaneously break the lattice symmetry.

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Silver zirconium nitride films deposited by unbalanced magnetron sputtering were studied by means of x-ray diffraction, transmission electron microscopy, x-ray photoelectron spectroscopy, spectroscopic ellipsometry, and nanoindentation. Coatings were deposited on silicon substrates at room temperatures with bias voltages in the −45 to −160 V range. The concentration of zirconium and silver was regulated by controlling the power to the sputtering guns. The nitrogen concentration was selected so that the nitrogen flow rate corresponded to the production of stoichiometric zirconium nitride. The films consisted of nanocrystals of zirconium nitride embedded in a silver matrix. The grain size was deduced from the width of the XRD peaks using the Scherrer formula and was found to decrease with the addition of silver. The chemical and phase composition was determined from XPS measurements. The optical constants were measured using spectroscopic ellipsometry. A correlation between film structure/composition and optical constants was established. The mechanical properties of the coatings were evaluated using nanohardness testing and were found to depend on composition and deposition parameters. Optimum mechanical properties were achieved for a silver content of 6% and a substrate bias of −160 V.