Impact of Mn Alloying on Phase Stabilities, Magnetic Properties and Electronic Structures in Fe

Impacts of Mn alloying on lattice stabilities, magnetic properties, electronic structures of the bcc and fcc phases and the fcc -> bcc phase transition in Fe16-xMnx (x = 0, 1 and 2) alloys are studied by first-principles calculations. Results show that the doped Mn atom prefers ferromagnetic and antiferromagnetic interaction with the host Fe atoms in the bcc and fcc phases, respectively. In these two phases, the magnetic moment of Mn is smaller and larger than Fe, respectively. The local moment of Fe is decided by the Fe-Mn distance in the bcc phase, whereas in the fcc phase, it is determined by spatial orientation with Mn. In the different phases, Mn prefers different site occupations, which can be understood from the electronic density of states near Fermi energy, implying a possibility of element redistribution during phase transition. The driving force of phase transition decreases with Mn alloying. Both destabilized bcc phase and stabilized fcc phase contribute to the inhibited phase transition, but the latter plays a dominant role. Antiferromagnetism is recognized as the key reason for the enhanced stability of the fcc phase by Mn alloying.

Automated summary

The impacts of Mn alloying on lattice stabilities, magnetic properties, electronic structures, and phase transitions in Fe16-xMnx alloys (x = 0, 1, and 2) have been studied using first-principles calculations. The results show that Mn prefers ferromagnetic and antiferromagnetic interactions in the bcc and fcc phases, respectively. The magnetic moment of Mn is smaller and larger than that of Fe in the bcc and fcc phases, respectively. The site occupations of Mn in different phases can be understood from the electronic density of states near the Fermi energy, suggesting the possibility of element redistribution during phase transitions. The antiferromagnetism is identified as the main reason for the enhanced stability of the fcc phase by Mn alloying.