title: Pressure-induced superconducting state of europium metal at low temperatures.
abstract: Divalent Eu (4f;{7}, J=7/2) possesses a strong local magnetic moment which suppresses superconductivity. Under sufficient pressure it is anticipated that Eu will become trivalent (4f;{6}, J=0) and a weak Van Vleck paramagnet, thus opening the door for a possible superconducting state, in analogy with Am metal (5f;{6}, J=0) which superconducts at 0.79 K. We present ac susceptibility and electrical resistivity measurements on Eu metal for temperatures 1.5-297 K to pressures as high as 142 GPa. At approximately 80 GPa Eu becomes superconducting at T_{c} approximately 1.8 K; T_{c} increases linearly with pressure to 2.75 K at 142 GPa. Eu metal thus becomes the 53rd known elemental superconductor in the periodic table.
authors.affiliation: Department of Physics, Washington University, CB 1105, One Brookings Drive, Saint Louis, Missouri 63130, USA.
authors.forename: M
authors.initials: M
authors.lastname: Debessai
authors.forename: T
authors.initials: T
authors.lastname: Matsuoka
authors.forename: J J
authors.initials: JJ
authors.lastname: Hamlin
authors.forename: J S
authors.initials: JS
authors.lastname: Schilling
authors.forename: K
authors.initials: K
authors.lastname: Shimizu