Dresden 2014 – wissenschaftliches Programm

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HL: Fachverband Halbleiterphysik

HL 114: Oxides: Bulk, films and interfaces

HL 114.7: Vortrag

Freitag, 4. April 2014, 11:15–11:30, POT 251

Formation of stable bound magnetic polarons in depleted ZnCoO films — •T. Kaspar¹, D. Bürger¹, I. Skorupa², O.G. Schmidt^{1, 3}, and H. Schmidt¹ — ¹TU Chemnitz, 09111 Chemnitz, Germany — ²Helmholtz-Zentrum Dresden-Rossendorf, 01314 Dresden, Germany — ³IFW Dresden, 01069 Dresden, Germany

Metal-semiconductor field effect transistors (MESFET) with a paramagnetic ZnCoO [1] channel and a free charge carrier concentration below the metal insulator transition [2] have been fabricated by pulsed laser deposition on c-plane sapphire substrates. The unstructured ZnCoO films reveal a positive magnetoresistance due to s-d- exchange interaction effects. We show that the formation of stable BMPs with a stable defect [3] is responsible for switching depleted ZnCoO from a low into a high resistance state by applying an external magnetic field. The high resistance state is persistent until the MESFET is heated up to 300 K and is caused by the formation of stable bound magnetic polarons (BMPs) in depleted ZnCoO. This effect could be possibly used for the realization of nonvolatile spin valves in ZnCoO films with two gate contacts. [1] T. Kaspar et al., IEEE 34, 1271 (2013) [2] Q.Y. Xu et al., J. Appl. Phys. D-Appl. Phys. 42, 085001 (2009); Phys. Rev. B 73, 205342 (2006); Phys. Rev. B. 76, 134417 (2007) [3] H. Schmidt et al., Appl. Phys. Lett. 91, 232110 (2007).