Josephson plasma resonance crossing the second peak; first order nature ofthe Bragg-to-vortex glass transition

Here we report the detailed and quantitative study of the Josephson couplin g energy in the vortex liquid, Bragg glass and vortex glass phases of Bi2Sr 2CaCu2O8+delta by the Josephson plasma resonance. The measurements revealed distinct features in the T- and H-dependencies of the Josephson plasma fre quency omega (pl) for each of these three vortex phases. When going across either the Bragg-to-vortex glass or the Bragg-to-liquid transition line, om ega (pl) shows a dramatic change. We provide a quantitative discussion on t he properties of these phase transitions. (C) 2001 Elsevier Science B.V. Al l rights reserved.