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The family of phthalocyanine (Pc) is suitable functional molecules in the field of molecular electronics because of their thermal stability and the possibility to tune their structure, chemical, magnetic, and transport properties by means of different metallic cations within the Pc molecular cage. Here we report the depth dependent chemical composition and magnetization of iron phthalocyanine (FePc), cobalt phthalocyanine (CoPc) and binuclear (Co–Fe)-phthalocyanine [(Co–Fe)Pc] thin films grown on sapphire substrates by molecular beam epitaxy. The binuclear (Co–Fe)Pc films grown by coevaporation of pure FePc and CoPc exhibited a new structure (binuclear) which show drastically different conducting and magnetic properties. Using X-ray reflectivity (XRR) and polarized neutron reflectivity (PNR), we demonstrated that the structural changes in binuclear (Co–Fe)Pc films as compared to pure film is responsible for about three to four order reduction in resistivity and presence of ferromagnetism in this film at low temperature. PNR data clearly suggest that the binuclear (Co–Fe)Pc film is ferromagnetic with a magnetization of 50 ± 15 kA/m at 10 K, indicating an increase in magnetic transition temperature. However, the pure FePc or CoPc films show negligible magnetization at 10 K. PNR data in combination of XRR also revealed detail magnetic and chemical structure across the molecule which is highly correlated along the normal and in the plane of the film.

Hetero-nanostructures having multi-layered ferromagnetic–antiferromagnetic ultrathin films, dispersion of ferromagnetic particles to the antiferromagnetic matrix, and a core–shell model (F@AF) can exhibit an exchange bias (HEB) that will be useful for spintronic materials such as spin valves, magnetic random-access memories, and ultrahigh data storage. The spin proximity effect of F and AF in the monodispersed core–shell is not much reported. For the first time, we report the preparation of core–shell monodispersed nanoparticles of γ-Fe2O3@MnxOyhaving different thicknesses of shells. The microscopic origin of magnetic properties and the microscopic crystal structure are explained by experimental results such as energy-dispersive analysis of X-rays line scanning, X-ray absorption near-edge spectroscopy, and magnetic data. The values of HEBfor γ-Fe2O3@MnxOy(Mn6) and γ-Fe2O3@MnxOy(Mn12) are found to be 8 and 79 Oe, respectively. Also, possible theoretical models such as crystal field stabilization energy for normal or inverse spinel structures and possible magnetic proximity interactions in core@shell models are discussed. Interestingly, samples show the heating behavior required for hyperthermia under an AC magnetic field, and materials will be potential for hyperthermia cancer therapy. Thermal decomposition of γ-Fe2O3@MnxOyproduces α-Fe2–2xMn2xO3at 550 °C, but their unit cell volumes are almost the same even after occupancy of 12 at. % Mn3+in Fe3+sites, and the origin of this behavior is explained for the first time.