Depth Resolved Magnetic Studies of Fe/57Fe/C60 Bilayer Structure Under X-Ray Standing Wave Condition

Abstract

Organic spintronics has emerged as a promising field for exploring novel spin-based phenomena and devices, offering the potential for low-power, flexible, and biocompatible electronics. The interface between metallic ferromagnetic and semiconducting organic layers plays a pivotal role in spin injection, transport, and extraction processes in these devices. Therefore, achieving a comprehensive understanding of the magnetic properties at these interfaces is essential for advancing device performance and functionality. This work explores the magnetic properties at the interface between thin Fe film and the C₆₀ layer. We employ a multi-technique approach, combining the magneto-optic Kerr effect, which provides a global assessment of magnetic properties, and depth-resolved grazing incidence nuclear resonance scattering (GINRS) under X-ray standing wave conditions, enabling us to probe magnetism with high spatial resolution within the interfacial region. GINRS measurements reveal intriguing behavior at the interface, characterized by reduced hyperfine fields in diffused ⁵⁷Fe layers. This observation suggests the formation of superparamagnetic clusters, which significantly influence the magnetic properties at the interface. These findings provide valuable insights into the complex interplay between ferromagnetic materials and organic semiconductors at the nanoscale, offering potential avenues for tailoring magnetoresistance effects in organic spintronic devices and contributing to the fundamental understanding of spin-dependent phenomena in organic spintronics.