Ferromagnetism in amorphous MgO


DURANDURDU M.

PHILOSOPHICAL MAGAZINE, vol.97, no.24, pp.2129-2141, 2017 (SCI-Expanded) identifier

  • Publication Type: Article / Article
  • Volume: 97 Issue: 24
  • Publication Date: 2017
  • Doi Number: 10.1080/14786435.2017.1328134
  • Journal Name: PHILOSOPHICAL MAGAZINE
  • Journal Indexes: Science Citation Index Expanded (SCI-EXPANDED), Scopus
  • Page Numbers: pp.2129-2141
  • Abdullah Gül University Affiliated: Yes

Abstract

We report, for the first time, the atomic structure of amorphous MgO based on ab initio molecular dynamics simulations. We find that its main building blocks are four-fold and five-fold coordinated configurations, similar to those formed in the liquid state. Its average coordination is estimated to beabout 4.36. The amorphous form having a perfect stoichiometry has a band gap energy of 2.4eV. On the other hand, Mg vacancies induce an insulator to metal transition and ferromagnetism in amorphous MgO whilst O vacancies do not cause such a transition, implying that the magnetism in amorphous MgO is related to the non-stoichiometry and Mg vacancies. With the application of pressure, the stoichiometric and non-stoichiometric (Mg vacancies) models undergo a phase transformation into a rocksalt state, suggesting that the electronic structure of the initial configurations has no influence on the resulting high-pressure phase in amorphous MgO.