An artificial cuprate compound belonging to the BiSrCaCuO family with eight adjacent sequetially imposed layer epitaxy. This compound undergoes a five order of magnitude resistivity drop with an onset near 280 kelvin and an offset at 250 kelvin. It exhibits a diamagnetic variation of susceptibility and magnetization below 290 kelvin. Additional observed features, such as strongly nonlinear conductivity, suggests superconductivity as a plausible explanation of the properties of this compound.

A more effective experimental method is used to analyze the effect of magnetic damping on a nonferromagnetic air track. Due to the continuous interaction between the horizontal air track and the moving magnets fixed on the air-track glider, the experiment can be easily done with low-cost photoelectric detecting techniques. A simple model is proposed based on Faraday’s law, the Lorentz force law, and Ampere’s law. Analytic expressions for the position, the velocity, and the magnetic damping force of the moving magnets as a function of time are obtained. Systematic measurements were performed and the results are in good agreement with the model. The method provides a simple teaching platform for introductory physics demonstrations and undergraduate courses in experimental physics.

Thin films of infinite layer compounds were prepared by molecular beam epitaxy. Defect layers were incorporated into the structure in order to dope the infinite layer phase. Hole type doping is usually observed. Resistivity measurements show that the conduction mechanisms change gradually with increasing doping level, from activational type to variable range hopping (or a mechanism governed by the Coulomb interaction between localized electrons) and then further to a mechanism related to weak localization which can be described by Δρ=T−S, where the exponent S ranges from 0.5 to 1.5.

The superconducting YBa2Cu3O7−x (YBCO) films have been deposited directly on silver (Ag) substrates by metalorganic chemical vapor deposition. Critical current density (Jc) as high as 1.4×104 A/cm2 (0 T, 77.3 K) was obtained. The high Jc was attributed to the small, compact grains of the YBCO films.