High field linear magnetoresistance in fully spin-polarized high-temperature organic-based ferrimagnetic semiconductor V(TCNE)x films, x ∼∼ 2

Positive magnetoresistance (MR) has been observed to increase linearly up to 32 T in the magnetically ordered state of organic-based ferrimagnetic semiconductor V(TCNE)x films (x  ∼∼2; TCNE = tetracyanoethylene) with TcTc above room temperature (>350>350 K). In this material conductivity takes place via electrons activated from 3d level of V2+ to upper ππ* subband of [TCNE] −−. We show an unusual MR behavior without any sign of saturation up to a magnetic field of 32 T. For temperatures less than TcTc MR exhibits a linear behavior in the entire field range and above TcTc it has a quadratic dependence at low fields. Temperature and field dependent behaviors of MR in this material are explained on the basis of spin polarizations in V2+ 3d level and the upper ππ* subband of [TCNE] −− formed by Coulomb repulsion.