Spin valve effect and high field magnetoresistance in hybrid magnetic tunnel junction of V(TCNE)$_{x~2}$/rubrene/ La$_{2/3}$Sr$_{1/3}$MnO$_{3}$

Molecule/organic-based magnets, that allow chemical tuning of electronic and magnetic properties, are a promising new class of magnetic materials for future spintronics [1]. V (TCNE:tetracyanoethylene)$_{x}$ ($x \sim$ 2) is the room temperature organic-based magnetic semiconductor ($T_c \sim$ 400 K). It has ferrimagnetic coupling between the spins in the TCNE$^{-}$ anions and spins in V$^{\rm II}$ leading highly spin- polarized valence and conduction bands. In this talk, we present realization of an organic-based magnetic as an electron spin polarizer in the standard spin valve device geometry [2]. The room temperature organic-based magnet, V(TCNE)$_x$ was successfully incorporated into the standard magnetic tunnel junction devices in tandem with LSMO (La$_{2/3}$Sr$_{1/3}$MnO$_3$) film. Beside spin valve effect, the device exhibits large negative high-field magnetoresistance, which may be associated with anomalous field dependent Fermi level shift in LSMO.\\[4pt] [1] A.J. Epstein, MRS Bull. ${\b 28}$, 492 (2003)\\[0pt] [2] Yoo et al., Nature Materials ${\b 9}$, 638 (2010)