講演会のお知らせ （11/21： Prof. Morten Ring Eskildsen
Department of Physics, University of Notre Dame ）

演題：「Vortex lattice anisotropy and pairing symmetry of Sr₂RuO₄」
講師：　Prof. Morten Ring Eskildsen
Department of Physics, University of Notre Dame
日時：１１月２１日　１６：３０－１７：３０
場所：コラボレーション棟３階 コラボレーション室
概要：
　Despite intense studies the exact nature of the order parameter in superconducting Sr₂RuO₄ has remained elusive. Multiple experimental and theoretical studies provide compelling support for triplet pairing and an odd-parity, p-wave order parameter symmetry. At the same time, seemingly contradictory experimental results have left important open questions concerning the detailed structure and coupling of the orbital and spin parts of the order parameter. One example of this predicament is conflicting evidence as to whether the p-wave order parameter is chiral.
Here we present the results of small-angle neutron scattering studies of the vortex lattice in Sr₂RuO₄ with the field applied close to the crystalline basal plane. Taking advantage of the transverse magnetization in this highly anisotropic superconductor, we were able to measure the vortex lattice anisotropy as a function of the field angle. From the measurements we were able to determine the intrinsic superconducting anisotropy between the c-axis and the Ru-O basal planes (~60), which greatly exceeds the upper critical field anisotropy (~20). This imposes significant constraints on possible models of triplet pairing in Sr₂RuO₄ and raises questions concerning the direction of the zero spin projection axis.

問い合わせ先：物理学科　市岡　（内線７８０６）