First-principle investigations of structure, elastic and bond hardness of FexB (x=1, 2, 3) under pressure

First-principles calculations are performed to study pressure effects on structure, magnetic and mechanical properties of FexB (x=1, 2, 3) compounds using density functional theory (DFT) within GGA approximation. The three structures are studied in the pressure range from 0 to 90 GPa, in order to predict the critical transition pressure from magnetic to nonmagnetic states (NM) and a possibility of superconductivity in this state was predicted. The density of states of FexB ferromagnetic compounds are significantly modified with increasing pressure and at particular critical pressures, our compounds undergo an abrupt loss of ferromagnetic character that cause mirror in upper and lowers half panels on both spin channels. Furthermore, the relationship between crystal structure and material hardness of Fe-x B is also investigated by calculating hardness of Fe-B and B-B bonds using Mulikan population analysis and semi empirical hardness theory. This model proved effective in hardness prediction of metal borides and agrees well with the experimental values. By the elastic stability criteria, it is predicted that FexB are stable up to the selected pressures. (C) 2016 Elsevier B.V. All rights reserved.