Quasiparticle Excitations outside the Vortex Cores in MgB$_2$ Probed by Muon Spin Rotation

Kazuki Ohishi; Takahiro Muranaka; Jun Akimitsu; Akihiro Koda; Wataru Higemoto; Ryosuke Kadono

doi:10.1143/JPSJ.72.29

paper

Quasiparticle Excitations outside the Vortex Cores in MgB $_{2}$ Probed by Muon Spin Rotation

arXiv:cond-mat/0212022 · doi:10.1143/JPSJ.72.29

Abstract

The magnetic penetration depth $λ$ in the mixed state of MgB $_{2}$ has been determined microscopically from the field distribution around magnetic vortices probed by muon spin rotation. Both the temperature and magnetic field dependence of $λ$ strongly suggest the presence of delocalized quasiparticles around the vortex cores. In particular, the effect of Doppler shift has been clearly observed as a finite gradient of the field dependence of $λ$ , strongly suggesting an anisotropic order parameter with the region of a vanishingly small energy gap.

4 pages, 3 figures included. to be published in J. Phys. Soc. Jpn

Quasiparticle Excitations outside the Vortex Cores in MgB2​ Probed by Muon Spin Rotation

Abstract

Quasiparticle Excitations outside the Vortex Cores in MgB $_{2}$ Probed by Muon Spin Rotation