New experimental evidence for Podkletnov effect

Abstract: In the works of E. Podkletnov et al. (for example [Physica C: Superconductivity, 1992, Vol. 203, p. 441]), a unique experiment is described in which a significant reduction in the weight of various test bodies was observed when placed above a rotating disk made of the superconductor YBa2Cu3O6+delta (YBCO); the disk was in the superconducting state (at 20-70 K) and was subjected to an alternating (50 Hz-100 MHz) magnetic field. Numerous attempts to replicate this experiment in other laboratories have been unsuccessful; however, a broad discussion has been initiated regarding the possible nature of the "Podkletnov effect" - the weight loss of objects located above the superconductor. In the present experimental work, results similar to the Podkletnov effect have been obtained, which, however, occur at room temperature. During our experiments, gas-tight containers with the crystal hydrate K2CO3X1.5H2O and dispersed YBCO exhibited a sharp loss of part of their weight during and after 0.5 hours of exposure to a magnetic field with a frequency of 50 MHz. Changes in the weight of various test bodies located in close proximity to the containers were recorded. It was found that these weight changes correlate with the external surface area of the bodies and do not depend on their chemical nature. A dependence of the magnitude of weight changes on the oxygen content in YBCO was obtained, which shows a significant dip in the region where superstructural orderings of the oxygen sublattice exist in the basal plane. This dip coincides in shape with the well-known dip in the dependence of Tc on delta (the "60-K plateau"). The possible connection between these two extraordinary phenomena coexisting in YBCO compounds - inexplicable weight changes and high-temperature superconductivity - is discussed.