Reduction formed europium (II) oxide thin films for cryogenic magneto-optic applications

Magneto-optic materials have significant potential in next generation photonic integrated circuits (PICs) as a tool for optical modulation and isolation. Europium (II) oxide (EuO) is a ferromagnetic semiconductor that exhibits a strong interaction with the magneto-optic Faraday effect and magneto-optic Kerr effects (MOKE). In this study, PIC compatible europium oxide thin films were deposited on silicon substrates via reductive sputtering. The films were tested for their magnetic and material properties via vibrating sample magnetometry and depth profiling x-ray photoelectron spectroscopy. The films show soft ferromagnetic EuO, with coercivity values as low as 59.3 Oe and the expected ferromagnetic magnetic transition at the Curie temperature (TC) of 69 K. This low TC limits room temperature applications, but has significant potential in the growing field of cryogenic computing systems.