Long range triplet Josephson current and 0−π transitions in tunable domain walls

Abstract

The order parameter of superconducting pairs penetrating an inhomogeneous magnetic material can acquire a long range triplet component (LRTC) with non-zero spin projection. This state has been predicted and generated in proximity systems and Josephson junctions. We show, using a realistic domain wall of an exchange spring bilayer, how the LRTC emerges and can be tuned with the twisting of the magnetization. We also introduce a new kind of Josephson current reversal, the singlet-LRTC 0– π transition, that can be observed in one and the same system either by tuning the domain wall or by varying temperature.

Keywords

• magnetic Josephson junction
• long range triplet component
• magnetic domain wall
• current reversal
• singlet-triplet mixing
• 74.50.+r