The origin of paramagnetic magnetization in field-cooled YBa2Cu3O7 films

Temperature dependences of the magnetic moment have been measured in YBa_2Cu_3O_{7-\delta} thin films over a wide magnetic field range (5 <= H <= 10^4 Oe). In these films a paramagnetic signal known as the paramagnetic Meissner effect has been observed. The experimental data in the films, which have strong pinning and high critical current densities (J_c ~ 2 \times 10^6 A/cm^2 at 77 K), are quantitatively shown to be highly consistent with the theoretical model proposed by Koshelev and Larkin [Phys. Rev. B 52, 13559 (1995)]. This finding indicates that the origin of the paramagnetic effect is ultimately associated with nucleation and inhomogeneous spatial redistribution of magnetic vortices in a sample which is cooled down in a magnetic field. It is also shown that the distribution of vortices is extremely sensitive to the interplay of film properties and the real experimental conditions of the measurements.Comment: RevTex, 8 figure

Origin of high- and low-conductance traces in alkanediisothiocyanate single-molecule contacts

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Origin of paramagnetic magnetization in field-cooled YBa2Cu3O7–delta films

Temperature dependences of the magnetic moment have been measured in YBa2Cu3O72d thin films over a wide magnetic-field range (

Attenuation of Conductance in Cobalt Extended Metal Atom Chains

Density functional theory, in conjunction with nonequilibrium Green's functions, is used to explore the attenuation of the resistance of Co x wires along the series Co 3(dpa) 4(NCS) 2, Co 5(tpda) 4(NCS) 2, and Co 7(teptra) 4(NCS) 2. At very low bias (0 &lt; V &lt; 25 mV) the conductance, G, decreases in the order G(Co 3) &gt; G(Co 5) &gt; G(Co 7), consistent with experiment and with an anticipated inverse relationship between conductance and chain length. At higher voltages, however, the current-voltage responses of all three are striking nonlinear, and above 50 mV G(Co 5) &gt; G(Co 3) &gt; G(Co 7). The very different behavior of the members of this homologous series can be traced to the different symmetries and multiplicities of their respective ground states, which in turn control the properties of the dominant transport channels. © 2012 American Chemical Society