Growth of ferromagnetic Co2FeSi films on flexible Ge(111)

For flexible semiconductor spintronic devices, we explore the growth of one of the ferromagnetic full-Heusler alloys, Co2FeSi, on a (111)-oriented pseudo-single-crystalline Ge/polyimide flexible template. Using a low-temperature molecular beam epitaxy (MBE) technique, crystalline Co2FeSi films are obtained on the flexible Ge at less than 80 °C. An MBE-grown Ge layer on the flexible Ge enables to improve magnetic properties of the Co2FeSi films. This work is an important step of high-performance flexible spintronics with ferromagnetic full-Heusler alloys.