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Magnetic and transport measurements have been performed in high quality YBa 2 Cu 3 O 72d single crystals. We demonstrate for the first time that the magnetization peak line in the phase diagram of YBa 2 Cu 3 O 72d , H p ͑T͒ exhibits an impressive similarity with the equivalent line for Bi 2 Sr 2 CaCu 2 O 8 . Our results show not only a similar temperature dependence but also an almost identical response to oxygen doping and a correlation to the multicritical point. At high temperatures we observe a previously unreported splitting of the magnetization peak. [S0031-9007(97)

Metamaterials offer the prospect of new science and applications. They have been designed by shaping or changing the material of the individual meta-molecules to achieve properties not naturally attainable. Composite meta-molecules incorporating a magnetic component offer new opportunities. In this work we report on the interaction between a non-magnetic split ring resonator (SRR) and a thin film of yttrium iron garnet (YIG). Strong hybridized resonances are observed. While the SRR is characterized by a magnetic and electric resonance, in practice, it is found that the YIG couples strongly to this symmetric (electric) mode of the SRR. It is also demonstrated that the anti-crossing region provides fertile ground for the creation of elementary excitations such as backward volume magnetostatic waves.

We study numerically the dynamics of two-dimensional vortex systems at zero temperature. In addition to pinned states and turbulent plastic flow, we find motion of vortices in rough channels along the direction of the driving force. In this decoupled channel regime we demonstrate how topological defects mediate the phase slip of different channels moving with different velocities. We thus provide important confirmation of recent analytical work describing vortex dynamics at high driving forces such as the moving glass theory of Giamarchi and Le Doussal. For the largest driving forces we find that the channels couple and observe elastic motion.Comment: 13 pages, 11 figures, RevTeX, final version, added Refs [15] and [35