Title: Effectiveness of organic molecules for spin filtering in an organic spin valve: Reaction-induced spin polarization for Co atop Alq(3)
Authors: Tu-Ngoc Lam
Lai, Yu-Ling
Chen, Chih-Han
Chen, Po-Hung
Chan, Yuet-Loy
Wei, Der-Hsin
Lin, Hong-Ji
Chen, C. T.
Wang, Jeng-Han
Sheu, Jeng-Tzong
Hsu, Yao-Jane
Department of Materials Science and Engineering
Issue Date: 21-Jan-2015
Abstract: The spin polarization of organic-ferromagnetic interfaces in an organic spin valve critically affects the efficiency of spin injection or detection. We examined the chemical and electronic properties of ferromagnetic Co deposited on organic Alq(3) and the interfacial spin-polarized capability of the electronic states. Our x-ray photoemission spectra and calculations with density-functional theory indicate a sequential and unequal distribution of charge from Co clusters to N and then to O atoms in Alq(3). The preferential orbital hybridization at specific functional sites produces efficient spin polarization of organic molecules. Element-specific measurements of x-ray magnetic circular dichroism demonstrate the preferential spin polarization in the lowest unoccupied molecular orbital state of N atoms at the complex interface for Co atop Alq(3), which agrees satisfactorily with calculation. Our results indicate that an induced interfacial spin polarization on engineering the dominant reaction of Co with mainly N and O atoms in Alq(3) might pave a way for effective spin filtering in organic spintronics.
URI: http://dx.doi.org/10.1103/PhysRevB.91.041204
ISSN: 1098-0121
DOI: 10.1103/PhysRevB.91.041204
Volume: 91
Appears in Collections:Articles