arXiv subjects

L. Dobrosavljević-Grujić

Publications and source records attributed to L. Dobrosavljević-Grujić.

2 recordsLinked to original sources

arXiv2000

Spin paramagnetism in d-wave superconductors

The Ginzburg-Landau equations are derived from the microscopic theory for clean layered superconductors with $d_{x^2-y^2}$ pairing symmetry, including the Pauli paramagnetism effect. The upper critical field $H_{c2}$ parallel to the $c$ axis is calculated. A comparison with the experimental data for YBCO suggests that, relative to the orbital effect, the Pauli paramagnetism contribution to $H_{c2}$ is significant. The reversible magnetization $M$ in high magnetic fields is also calculated, showing strong temperature dependence of the slope $dM/dH$, as a consequence of the spin paramagnetism. A simple expression for the high temperature spin susceptibility is derived, in a good agreement with the Knight shift measurements on YBCO.

cond-mat.supr-con↗

arXiv1999

Quasiparticle energy spectrum in ferromagnetic Josephson weak links

The quasiparticles energy spectrum in clean ferromagnetic weak links between conventional superconductors is calculated. Large peaks in DOS, due to a special case of Andreev reflection at the ferromagnetic barrier, correspond to spin-splitt bound states. Their energies are obtained as a function of the barrier thickness, exchange field strength, and of the macroscopic phase difference $ϕ$ at the link, related to the Josephson current. In the ground state, $ϕ$ can be 0 or $π$, depending on the ferromagnetic barrier influence. Conditions for the appearence of the zero-energy bound states (ZES) and for the spin polarized ground state (SPGS) are obtained analytically. It is shown that ZES appear only outside the weak link ground state.

cond-mat.supr-con↗