High-temperature superconductivity in transition metal oxypnictides: A rare-earth puzzle?

Enhanced superconductivity by rare-earth metal doping in phenanthrene.

We successfully synthesized La- and Sm-doped phenanthrene powder samples and observed superconductivity in them at T(c) around 6 K. The T(c)s are 6.1 K for La(1) phenanthrene and 6.0 K for Sm(1) phenanthrene, which are enhanced by about 1 and 0.5 K compared to those in A(3) phenanthrene (A = K and Rb) and in Ae(1.5) phenanthrene (Ae = Sr and Ba) superconductors, respectively. The superconductiv...

Ternary Rare Earth Transition Metal Zinc Compounds

Forty eight new com pounds RT2Z n2o were prepared by annealing cold-pressed pellets o f the elem ental com ponents in an argon atm osphere. They crystallize with the cubic CeCr^Abo type structure (Fd3m , Z = 8), which was refined from single-crystal diffractom eter data o f TbFeiZn^o (a = 1411.1(1) pm), Y Ru2Z n2o (a = 1422.6(1) pm), D yRu2Z n2o (a = 1422.1(1) pm), G dC o2Z n2o (a = 1406.0(1) p...

High-temperature superconductivity from fine-tuning of Fermi-surface singularities in iron oxypnictides

In the family of the iron-based superconductors, the REFeAsO-type compounds (with RE being a rare-earth metal) exhibit the highest bulk superconducting transition temperatures (Tc) up to 55 K and thus hold the key to the elusive pairing mechanism. Recently, it has been demonstrated that the intrinsic electronic structure of SmFe0.92Co0.08AsO (Tc = 18 K) is highly nontrivial and consists of mult...

Spectroscopic studies of metal high-k dielectrics: transition metal oxides and silicates, and complex rare earth/transition metal oxides

G. Lucovsky 1, 2, , J. G. Hong, C. C. Fulton, Y. Zou, R. J. Nemanich, H. Ade, D. G. Scholm, and J. L. Freeouf 5 1 Department of Physics, North Carolina State University, USA 2 Department of Materials Science & Engineering, North Carolina State University, USA 3 Department of Electrical & Computer Engineering, North Carolina State University, USA 4 Department of Materials Science & Engineering, ...

Correlations in rare-earth transition-metal permanent magnets