Calcium ferroelectric

Moriyoshi C, Kuroiwa Y, Masuno A, Inoue H (2012) Site-selective calcium substitution in BaTi205 effect on the crystal structure tmd the ferroelectric phase transition. J Phys Soc Jpn... 

Calzada, M.L. and Sirera, R. (1996) Chemically derived ferroelectric calcium modified lead titanate thin films deposited from aquo-diol solvent solutions. /. Mater. Set Mater. Electron., 7, 39. 

Fig. 1.16 Some ferroelectric compounds and their phase transition types and temperatures. Different thermal expansion of calcium barium niobate in [hfcO] and [001] direction. Cracking along [hkO) faces In potassium lithium niobate caused by crossing the phase transition temperature at about 450°C.

In addition to the studies on PZT, Glower et al. examined the ionic conduction in a ferroelectric material, Cao.iBao.9Ti03, by means of the same method as that used for PTZ [9]. They showed that the conduction in this oxide is ionie below 300°C, but electronic conduction appears sharply near 300°C and becomes predominant above 500°C. They identified the mobile ions as calcium ions by using so-called activation analysis, which was a kind of irradiation analysis of the surface of the solid after passing DC ciurent across the soUd conductor. 

Perovskite materials (ABX3) exhibit many fascinating properties from both theoretical and application perspectives, including ferroelectricity, superconductivity, charge ordering, and spin-dependent transport. The interplay of compositional, structural, optical, and transportation properties is commonly observed in this family, making them promising candidates as photocatalysts. Perovskites are characterised by a crystal structure similar to that of calcium titanium oxide (CaTiOs). Normally A and B sites are occupied by two cations with very different sizes (dA > dfi), whereas X (normally O) is an anion that bonds to both. In the ideal cubic-symmetry structure, the A and B cations are 12- and sixfold coordinated in bulk and surrounded by cuboctahedron and octahedron of anions, respectively. 

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