title: Multiple changes of order of the vortex melting transition in Bi2Sr2CaCu2O8 with dilute columnar defects.
abstract: A low concentration of columnar defects is reported to transform a first-order vortex lattice melting line in Bi2Sr2CaCu2O8 crystals into alternating segments of first- and second-order transitions separated by two critical points. As the density of columnar defects is increased, the critical points shift apart and the range of the intermediate second-order transition expands. The measurement of equilibrium magnetization and the mapping of the melting line down to 27 K was made possible by employment of the shaking technique.
authors.affiliation: Department of Condensed Matter Physics, Weizmann Institute of Science, Rehovot 76100, Israel. tal.hazak@weizmann.ac.il
authors.forename: T
authors.initials: T
authors.lastname: Verdene
authors.forename: H
authors.initials: H
authors.lastname: Beidenkopf
authors.forename: Y
authors.initials: Y
authors.lastname: Myasoedov
authors.forename: H
authors.initials: H
authors.lastname: Shtrikman
authors.forename: M
authors.initials: M
authors.lastname: Rappaport
authors.forename: E
authors.initials: E
authors.lastname: Zeldov
authors.forename: T
authors.initials: T
authors.lastname: Tamegai