Electric-field control of magnetoresistance

• Applicant: Professorin Dr. Heidemarie Schmidt
• Subject Area: Experimental Condensed Matter Physics
• Term: from 2009 to 2014
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 158026470

Field-Effect-Transistors with magnetoresistive conducting oxide channels look promising as an alternative design for Spin-Field-Effect-Transistors. We will use pulsed laser deposition with in-situ RHEED thickness control followed by photolithography/ion beam etching nanostructuring to fabricate these new magnetoresistance devices for semiconductor spintronics. The finite spin polarization in magnetic conducting oxides allows for the electric-field control of magnetoresistance. We aim to exploit the spin-splitting due to sd-exchange coupling being one order of magnitude larger than the spin-splitting due to the Rashba and Dresselhaus effect for electric-field control of magnetoresistance at elevated temperatures in n-type conducting, magnetic oxides. Furthermore, in order to investigate the even larger spin-splitting due to pd-exchange coupling in p-type conducting, magnetic oxides, we will also use pulsed laser deposition combined with a N ion/atom hybrid source to realize acceptor-like doping atoms into the magnetic oxides. The goal of the project is the electric-field control of the magnetoresistance in magnetic oxide active layers in Spin-Metal-Semiconductor-Field-Effect-Transistors and in Spin-Metal-Oxide-Semiconductor-Field-Effect-Transistor structures. Possibly new device functionalities will be probed on Field-Effect-Transistors with ferromagnetic source and drain contacts.

• DFG Programme: Research Grants