Substantially enhanced carrier mobility in graphene in proximity to ferromagnetic insulator EuS

The hybrid structure of graphene and ferromagnetic insulators is an emerging platform for achieving nontrivial effects in graphene via proximal coupling. However, the deposition of ferromagnetic insulators on graphene usually degrades the graphene's mobility. Here, we develop a substantially improved technique of fabricating a high-mobility graphene device capped by ferromagnetic insulating EuS layers. The improvement of the technique includes the deposition of EuS at a low temperature (similar to 80 K) and the adoption of a contamination-free method to fabricate electrodes. With these improvements, the mobility of graphene in proximity to EuS is enhanced to be as high as 18000-26000 cm(2)V(-1)s(-1). The high-mobility EuS-capped graphene may be a promising candidate for the realization of nontrivial quantum states at low magnetic fields. (C) 2017 The Japan Society of Applied Physics