Materials design of interstitial Be-doped ferromagnetic (In,Fe)As

Using the first-principles calculation method, we study the ferromagnetic states of electron-doped (In,Fe)As by the Korringa-Kohn-Rostoker coherent potential approximation method and calculate Curie temperature (T-c) by Monte Carlo simulation. We show that the chemical pair interactions and magnetic exchange interactions between Fe atoms depend on the concentration of the doped interstitial Be donor. We obtain the so-called ordered phase of Fe-rich regions in this material. With this type of structure, Be-doped (In,Fe)As can exhibit ferromagnetism and its T-c I could be up to approximately 85K. We propose that the ordered phase is necessary for enhancing ferromagnetism and increasing T-c. (C) 2014 The Japan Society of Applied Physics