Crystal structure of the antiferroelectric perovskite Pb₂MgWO₆

Prediction of the unit cell edge length of cubic A22+BB′O6 perovskites by multiple linear regression and artificial neural networks

“…The lengths of the unit cell edge (a/Å) for 147 perovskites of A 2 BB ′ O 6 type, with an (NH 4 ) 3 FeF 6 structure and Fm3m space group, were retrieved from the literature [1,[18][19][20][21][22][23][24][25][26][27][28][29][30][31][32][33]. In order to make comparisons between the two models, the data were divided randomly into two subsets: the calibration subset with 98 compounds and test subset with 49 compounds.…”

Étude de la Solution Solide Entre Tungstate et Tellurate de Magnésium: Pb2MgWxTe(1−x)O6

“…Pb MgWO pre´sente, a`312 K, une transition de phase nettement du premier ordre vers une phase antiferroe´lec-trique de syme´trie orthorhombique (4,5). La structure de cette phase a e´te´de´termine´e par Baldinozzi et al (6). Le groupe d'espace est Pmcn.…”

“…Le de´placement principal des atomes de plomb Pb, par rapport a`la structure cubique, s'effectue suivant une direction proche de [012] (qui correspond a`une direction 11002 ). Le plomb se rapproche de 4 atomes d'oxyge`ne et forme avec ces derniers une pyramide a`base carre´e peu de´forme´e dont il occupe le sommet (6). Le de´placement du Pb diminue avec la concentration en Te, entraıˆnant une augmentation des 4 distances courtes Pb-O (Tableau 4).…”

X-ray diffraction and dielectric studies across morphotropic phase boundary in (1−x) [Pb(Mg0.5W0.5)O3]–xPbTiO3 ceramics

“…This suggests that the structure of PMW-xPT for compositions with x > 0.68 is tetragonal, as of PbTiO 3 . The structure of pure PMW is known to be cubic in Fm3m space group above Curie temperature [15]. This is evident from Fig.…”

“…Thus the location of the MPB and structural studies on the MPB phases in PMW-xPT ceramics is ambiguous and incomplete. There are few reports [15] where Rietveld structural analysis of the PMW is done but such a study has still not been done on PMW-xPT ceramics.…”