C60-based hot electron Magnetic Tunnel Transistor

M. GOBBI; A. BEDOYA-PINTO; F. GOLMAR; R. LLOPIS; F. CASANOVA; L. HUESO

Parma

Conferencia; Joint European Magnetic Symposia 2012; 2012

Organic semiconductors (OS) have emerged as a promising material class for spintronic applications [1], mainly due to their weak spin relaxation mechanisms which result in long spin lifetimes. While recent efforts have focused on the spin injection and transport in organic semiconductors, the fact that OSs behave as ordinary semiconductors has not been fully exploited in organic spintronics yet. In this work, we report the achievement of a magnetic tunnel transistor (MTT) which employs C60 as a semiconducting collector. The MTT represents one of the most successful spintronic devices based on the combination between ferromagnetic materials and semiconductors [2]. MTTs are 3-terminal devices with the same scheme of a metal base transistor: a hot electron current is injected into the device by an emitter, and a spin-valve base modulates the amount of current reaching the collector. In this configuration, the current can be modulated not only by the applied gate voltage, but also by the magnetic field (magnetocurrent). We show that the C60-based MTT, composed of an Al/Al203/Co/Cu/Py/C60/Al multilayer, performs as state-of-the-art inorganic MTT with a magnetocurrent (MC) reaching 89% at room temperature. Moreover, we show that this MC value can be enhanced by the application of a proper voltage VBC at the collector, reaching 8500%. These results demonstrate that, for this application, C60 behaves as a conventional n-type inorganic semiconductor. In particular, the energy barrier at the C60/metal interface resembles a conventional Schottky barrier, and its height is directly determined. [1] V. A. Dediu, L. E. Hueso, I. Bergenti, and C. Taliani, Nature Materials, 8 707 (2009) [2] R. Jansen, Journal of Physics D: Applied. Physics 36 R289 (2003)