Ferromagnetism in amorphous MgO


DURANDURDU M.

PHILOSOPHICAL MAGAZINE, cilt.97, ss.2129-2141, 2017 (SCI İndekslerine Giren Dergi)

  • Cilt numarası: 97 Konu: 24
  • Basım Tarihi: 2017
  • Doi Numarası: 10.1080/14786435.2017.1328134
  • Dergi Adı: PHILOSOPHICAL MAGAZINE
  • Sayfa Sayısı: ss.2129-2141

Özet

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.