Energy level alignment and interactive spin polarization at organic/ferromagnetic metal interfaces for organic spintronics

Abstract

ABSTRACT:Energy level alignment and spin polarization at tetracyanoquinodimethane/Fe and acridine orange base/Fe interfaces are investigated by means of photoelectron spectroscopy and X-ray magnetic circular dichroism (XMCD), respectively, to explore their potential application in organic spintronics. Interface dipoles are observed at both hybrid interfaces, and the work function of Fe is increased by 0.7 eV for the tetracyanoquinodimethane (TCNQ) case, while it is decreased by 1.2 eV for the acridine orange base (AOB) case. According to XMCD results, TCNQ molecule has little influence on the spin polarization of Fe surface. In contrast, AOB molecule reduces the interfacial spin polarization of Fe significantly. Induced spin polarization of the two organic molecules at the interfaces is not observed. The results reveal the necessity of investigating the magnetic property changes of both the OSC and the FM during the process of energy level alignment engineering.

11,11,12,12‐Tetracyanonaphtho‐2,6‐quinodimethane in Contact with Ferromagnetic Electrodes for Organic Spintronics

“…NEXAFS and UPS/XPS results give the direct evidence of strong interaction and hybridization between TNAP molecule and Fe, and it is also interesting to know the induced magnetization in light elements of TNAP molecule by Fe electrode and counteraction effects on the magnetic property of Fe atoms by the molecules adsorbed . Figure shows XMCD spectra for N K‐edge (panel (a)) and Fe L‐edge (panel (b)) in total electron yield (TEY) mode for Fe/TNAP interface.…”

“…And from XPS results, there is a new peak around 398.45 eV for N 1s in ML TNAP on Fe, while it is difficult to see the new feature from the interaction with C atoms. [30] Figure 3 shows XMCD spectra for N K-edge (panel (a)) and Fe L-edge (panel (b)) in total electron yield (TEY) mode for Fe/TNAP interface. [29] Therefore, the interaction at Fe/TNAP may still preferentially happen between N and Fe atoms and partially between C and Fe atoms.…”

“…[30] In Figure 4, the sum rule analysis of Fe L-edge XMCD and NEXAFS for Fe and Fe/TNAP (ML) are given. [30] In Figure 4, the sum rule analysis of Fe L-edge XMCD and NEXAFS for Fe and Fe/TNAP (ML) are given.…”

Electronic and magnetic properties of TTF and TCNQ covered Co thin films

“…Spin-polarized microscopy and spectroscopy techniques have shown these effects to be typically spin dependent, resulting in a hybrid interface with magnetic properties that are quite different from those of the bulk ferromagnet. [13][14][15][16][17][18][19] It is a topic of active study how this effects the spin-transport across the interface. [20][21][22][23][24] In addition, the magnetic properties, such as the coercive field of the saturation magnetization, of ferromagnetic thin films may be tuned by the same interfacial effects.…”

Spintronic effects at nickel-graphene interfaces

“…At the interface between the materials phenomena like orbital hybridisation and charge transfer can greatly influence the transport of spins across the interface. Spin polarised microscopy and spectroscopy techniques have shown these effects to be typically spin dependent, resulting in a hybrid interface with magnetic properties that are quite different from those of the bulk ferromagnet (Djeghloul et al, 2013;Lach et al, 2012;Rizzini et al, 2014;Sun et al, 2014;Suzuki et al, 2002Suzuki et al, , 2004Tran et al, 2013). It is a topic of active study how this effects the spin transport across the interface Kawahara et al, 2012;Raman et al, 2013;Schmaus et al, 2011;Steil et al, 2013).…”