Investigations of Metal-Organic structures for applications in Organic Spin Valve devices

Abstract

Organic spintronics has drawn the interest of the science community due to various applications in spin-valve devices. But to date, an efficient room-temperature Organic Spin Valve device has not been experimentally realized due to the complicated spin transport at the metal-organic interfaces. These studies are always challenging due to the complicated spin-polarized charge transfer at the metal-organic interfaces. The present study focuses on a comprehensive understanding of the interfacial properties that are essential for advancing device performance and functionality. The Ferromagnetic metals and half-metallic electrodes such as Co, Co2FeAl, etc., and fullerene (C60) bilayer samples are prepared and studied via different structural and magnetic characterizations. Due to the mechanical softness of C60, deep penetration of ferromagnetic metal atoms is observed inside the C60 film. In-situ MOKE measurements reveal the origin of the 23 Å thick magnetic dead layer at the interface, which is attributed to the diffused ferromagnetic clusters exhibiting superparamagnetic behavior. In contrast to the inorganic substrates, magnetic anisotropy tends to develop at 40 Å thick Co film deposited on C60 which enhances with increasing thickness. The XRD measurements confirm the presence of in-plane compressive strain and texturing along the hcp (002) phase in the Co film. The anomaly observed in the hard axis of magnetization is due to high dispersion in the local magnetic anisotropy. The variation of the magnetic anisotropy axis is observed in the Co2FeAlwedge deposited in the proximity of C60. These findings provide valuable insights into the complex interplay between ferromagnetic materials and organic semiconductors offering potential avenues for tailoring magnetoresistance effects and fundamental understanding of organic spintronic devices.