Electronic structure of thin film iron-tetracyanoethylene: Fe(TCNE)x

Abstract

Thin film iron-tetracyanoethylene Fe(TCNE) x , x ∼ 2, as determined by photoelectron spectroscopy, was grown in situ under ultra-high vacuum conditions using a recently developed physical vapor deposition-based technique for fabrication of oxygen-and precursor-free organicbased molecular magnets. Photoelectron spectroscopy results show no spurious trace elements in the films, and the iron is of Fe 2+ valency. The highest occupied molecular orbital of Fe(TCNE) x is located at ∼1.7 eV vs. Fermi level and is derived mainly from the TCNE − singly occupied molecular orbital according to photoelectron spectroscopy and resonant photoelectron spectroscopy results. The Fe(3d)derived states appear at higher binding energy, ∼4.5 eV, which is in contrast to V(TCNE) 2 where the highest occupied molecular orbital is mainly derived from V(3d) states. Fitting ligand field multiplet and charge transfer multiplet calculations to the Fe L-edge near edge X-ray absorption fine structure spectrum yields a high-spin Fe 2+ (3d 6 ) configuration with a crystal field parameter 10Dq ∼ 0.6 eV

The iron L edges: Fe 2p X-ray absorption and electron energy loss spectroscopy

“…An important aspect of the simulations is the different covalency for electrons in different 3d orbitals [281]. Thin film iron complexes with tetracyanoethylene (tcne) have been studied by Bhatt et al [24]. tcne has four cyano groups attached to a central double bonded C C group, i.e.…”

Thin‐Film Deposition of an Organic Magnet Based on Vanadium Methyl Tricyanoethylenecarboxylate

“…These films show magnetic ordering at room temperature, opening the door to applications in organic spintronics including all‐organic spin valves and spin‐based light emitting diodes (spin‐LEDs) . An extensive array of organic‐based analogues in the M[TCNE] x family have been explored using high vacuum/temperature CVD or physical vapor deposition (PVD), including M = Co, Ni, Cr, Fe, Nb, and Mo; however, the relatively harsh film deposition conditions and lack of room temperature magnetic ordering limit their use in spintronics devices. As a result, parallel efforts have explored replacing TCNE with other organic single electron acceptors as an alternate route to synthesizing organic magnets with tunable magnetic properties and room‐temperature magnetic ordering .…”

Thin films of organic-based magnetic materials of vanadium and cobalt tetracyanoethylene by molecular layer deposition

“…1,5,13 Other than V [TCNE] x , CVD has also been used to grow thin lms of metal-TCNE complexes composed of other metal elements. 14,15 This includes an example of a solid solution that incorporates both V and Co. 16 Alternative to CVD, physical vapor deposition (PVD)-based reactive evaporation has also been employed to deposit thin lms of M [TCNE] x , 8,[17][18][19] however, organic-based magnets with mixed metals have not yet been made by this method. Originating from atomic layer deposition (ALD), molecular layer deposition (MLD) has drawn increasing attention in recent years.…”