PubMed Health⌕ Search

Biomedical subjects

E H Brandt

Publications and source records attributed to E H Brandt.

5 recordsLinked to original sources
PubMed2005

Equilibrium first-order melting and second-order glass transitions of the vortex matter in Bi2Sr2CaCu2O8.

The thermodynamic phase diagram of Bi2Sr2CaCu2O8 was mapped by measuring local equilibrium magnetization M(H,T) in the presence of vortex shaking. Two equally sharp first-order magnetization steps are revealed in a single temperature sweep, manifesting a liquid-solid-liquid sequence. In addition, a second-order glass transition line is revealed by a sharp break in the equilibrium M(T) slope. The first- and second-order lines intersect at intermediate temperatures, suggesting the existence of four phases: Bragg glass and vortex crystal at low fields, glass and liquid at higher fields.

Journal Article↗
PubMed2001

Charge profile in vortices.

The electric charge density in the vortex lattice of superconductors is studied within the Ginzburg-Landau (GL) theory. We show that the electrostatic potential varphi is proportional to the GL function, varphi /psi/2-/psi(infinity)/2. Numerical results for the triangular vortex lattice are presented.

Journal Article↗
PubMed2000

Meissner-London currents in superconductors with rectangular cross section.

Exact analytic solutions are presented for the magnetic moment and screening currents in the Meissner state of superconductor strips with rectangular cross section in a perpendicular magnetic field and/or with transport current. The extension to finite London penetration is achieved by an elegant numerical method which works also for disks. The surface current in the specimen corners diverges as l(-1/3) where l is the distance from the corner. This enhancement reduces the barrier for vortex penetration and should increase the nonlinear Meissner effect in d-wave superconductors.

Journal Article↗