Josephson current in d-wave superconductor junctions with ferromagnetic insulator

Abstract

We investigate the temperature dependence of the critical current and current-phase relation by taking into account the ferromagnetic scattering effect at interface in a d-wave superconductor (S)/ferromagnetic insulator layer (FI)/d-wave superconductor (S) junction. It is shown that both the barrier scattering and the roughness scattering at the interface always suppress the Andreev reflection. The Josephson critical currents depend to a great extent on the effective exchange field of the interface and the crystal orientation of the d-wave superconductor. The exchange field can lead to the change of the junction from 0 to π states and the alteration of the oscillation periods. It can also enhance the Josephson critical current in the junction under certain conditions.

Heat transport and electron cooling in ballistic normal-metal/spin-filter/superconductor junctions

“…Recently, influences of the spin-filter effect in ferromagnetic-semiconductors [12][13][14] on the proximity effect [15][16][17][18][19][20][21], the Josephson effect [22][23][24][25][26][27][28][29][30][31][32], and macroscopic quantum phenomena [33][34][35][36] have been investigated theoretically. Moreover, superconducting tunnel junctions with spin-filters have been also realized experimentally [37][38][39][40] In this work we propose an novel electron-cooler based on clean N/spin-filter/S junctions [see Fig.…”