Spin polarized coulomb blockade in metallic magnetic single electron transistors

• Applicants: Professor Dr. Jürgen König; Professor Dr. Günter Reiss; Privatdozent Dr. Hans-Werner Schumacher
• Subject Area: Experimental Condensed Matter Physics
• Term: from 2008 to 2013
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 73336480

Magneto electronics plays a major role in todays and future information technology. With steadily decreasing dimensions of future magneto electronics devices the charging energy increases and coulomb blockade effects may eventually dominate spin dependent transport. While various theoretical predictions on spin polarized coulomb blockade are available only very few experimental studies exist and a complete picture is lacking. Here we propose to study spin polarized coulomb blockade in the model system of a metallic magnetic single electron transistor (magSET) island coupled to ferromagnetic leads of well controlled spin polarization. The sub micron magSETs are fabricated from magnetic double barrier tunnelling junctions (DBTJ). In these devices the coercive field and the initial spin orientation of the leads is controlled by its growth parameters and coupling to antiferromagnetic layers. The proposed magSETs allow a precise control of the relative spin polarization of the two leads using a tilted magnetic field. The spin dependent single electron transport is characterized by low temperature magneto transport at mK temperatures in tilted magnetic fields. Additionally the spin dependent transport behaviour of the devices and the underlying mechanisms is analyzed theoretically and compared to the experimental observations. This project will for the first time allow a complete understanding of spin dependent single electron tunnelling in magnetic metallic single electron transistors.

• DFG Programme: Research Grants