Real-Time Monitoring the Growth of Epitaxial Co x Fe 3- x O 4 Ultrathin Films on Nb-Doped SrTiO 3 (001) via Reactive Molecular Beam Epitaxy by Means of Operando HAXPES.

In this work, we present a comprehensive study on real-time monitoring the growth of epitaxial Co x Fe 3- x O 4 thin films grown on SrTiO 3 (001) substrates via reactive molecular beam epitaxy. The growth process was monitored during evaporation by means of time resolved operando hard X-ray photoelectron spectroscopy (HAXPES). We prepared ultrathin ferrite films using different oxygen partial pressures, showing pure metallic, light oxidic, and cobalt ferrite-like growth. Additional X-ray diffraction measurements confirm HAXPES results.