“…In contrast to the traditional p-type Mn-doped FMSs such as (Ga,Mn)As, novel Fe-doped III-V FMSs have recently attracted much attention, because Fe-doped FMSs can accommodate both n-and p-type carriers and exhibit ferromagnetism with high Curie temperature T C (> 300 K) [5,9,10]. Using the p-type and/or n-type Fe-doped FMSs, spintronics devices have already been demonstrated [6,7,11,12]. (In 1−x ,Fe x )As codoped with Be (referred to as (In,Fe)As:Be hereafter) is the first n-type FMS [13,14], where the Be ions act as double donors [15].…”