Site occupancy effects of Mg impurities in BaTiO3

MACHADO, R.; DI LORETO, A.; SEPLIARSKY, M.; FRATTINI, A.; STACHIOTTI, M.G.

JOURNAL OF ALLOYS AND COMPOUNDS

ELSEVIER SCIENCE SA

Año: 2019 vol. 809

0925-8388

A first principles based atomistic model is developed to investigateintrinsic effects of Mg incorporation into A- and B-sites of BaTiO3.We find that the replacement ofBa by Mg at A-site positions generateslocal electric dipoles due to Mg off-centering along [001] directionswhich increase the Curie temperature anddecrease the cell volume. The inversedependence is observed for B-site doped compositions, where thedefect dipoles decrease the Curie temperature and expand the volume.Temperature-composition phase diagrams are constructed for both sitelocations and the effect of the two types of defects on the switchingprocess is investigated. Thetheoretical predictions are used to shed light on experimentalresults of Mg-doped ceramics manufactured to induce a givenoccupation site. Thecomparison indicates that the incorporation of Mg into the B-site isthermodynamically favorable whereas the properties observed for theA-site ceramics cannot be explained from the intrinsec effectsdescribed by the model.p { margin-bottom: 0.21cm; direction: ltr; color: rgb(0, 0, 10); }p.western { font-family: "Times New Roman", serif; font-size: 12pt; }p.cjk { font-family: "Times New Roman", serif; font-size: 12pt; }p.ctl { font-family: "Times New Roman", serif; font-size: 12pt; }a:link { }