Air-stable organic-based semiconducting room temperature thin film magnet for spintronics applications

Abstract

Herein, we report on a preparation method of vanadium tetracyanoethylene, V(TCNE)x, an organic-based semiconducting room temperature thin film magnet. Previously, this compound has been reported to be extremely air sensitive but this preparation method leads to V(TCNE)x, which can retain its magnetic ordering at least several weeks in air. The electronic structure has been studied by photoelectron spectroscopy and the magnetic properties by superconducting quantum interference device. The properties mentioned above, in combination with complete spin polarization, makes this air-stable V(TCNE)x a very promising material for spintronic devices.Original publication: Elin Carlegrim, Anna Kanciurzewska, Per Nordblad and Mats Fahlman, Air-stable organic-based semiconducting room temperature thin film magnet for spintronics applications, 2008, Applied Physics Letters, (92), 163308. http://dx.doi.org/10.1063/1.2916901. Copyright: American Institute of Physics, http://apl.aip.org/apl/top.js

Density functional study of the magnetic coupling inV(TCNE)2

“…However, the commercial use of V͑TCNE͒ 2 is currently limited as the material is amorphous and extremely air and water sensitive. 3,6,7,10,11 The lack of long-range order and the substantial influence of the synthetic procedure ͑i.e., starting materials, 3,25 solvent, 9 and preparation method 6,7,26,27 ͒ on the system properties clearly suggest that V͑TCNE͒ 2 compounds contain structural defects and impurities such as residual solvent and/or by-products. Furthermore, it is possible that multiple metastable structures are thermodynamically feasible under typical preparation conditions.…”

Investigation of thin films of organic-based magnets grown by physical vapor deposition

“…The spectrum for V[TCNE] 1.9 film shows a main peak around 398.5 eV with a broad shake-up band that is similar to the previously reported results. 9,11 However, in the N 1s spectrum of V[TCNE] 1.2 film, a shoulder at the low energy side of the main peak was observed. This shoulder may result from the alternative bonding between vanadium and TCNE due to the direct reaction of vanadium atoms to TCNE, which has been proposed for other metal/TCNE complexes made by the PVD-based methods.…”

“…15 This is qualitatively consistent with the result from previously reported V[TCNE] x made by PVD-based method and other methods. 9,11 The reason for the magnetization close to 400 K is not understood. This, either the delay of the structural rearrangement or any alternative structure that contributes to the magnetism, suggests the samples made from our method are more complicated in structure than previously reported V[TCNE] x .…”

“…[11][12][13][14] However, more information is still needed to further understand the nature of V[TCNE] x made from this method. In this work, the growth condition of V[TCNE] x films are studied in detail.…”

“…1 Thin films of V[TCNE] x were later deposited by several different techniques that include chemical vapor deposition (CVD), 9,10 physical vapor deposition (PVD), 11 and molecular layer deposition (MLD). 7 CVD has been the first and a promising method to deposit thin films of V[TCNE] x .…”