TY - JOUR
T1 - New 10-layer hexagonal perovskites
T2 - Relationship between cation and vacancy ordering and microwave dielectric loss
AU - Mallinson, P.
AU - Claridge, J. B.
AU - Iddles,
AU - Price, T.
AU - Ibberson, R. M.
AU - Allix, M.
AU - Rosseinsky, M. J.
PY - 2006/12/26
Y1 - 2006/12/26
N2 - The new ceramic materials Ba10Mg0.25Ta 7.9O30 and Ba10Co0.25Ta 7.9O30 have been synthesized in isolation and their dielectric and crystallographic properties characterized fully. The crystal structure determination, using a combination of X-ray and neutron powder diffraction and electron microscopy, reveals a 10-layer perovskite structure that involves the (hcccc)2 stacking sequence with a pair of face-sharing octahedral sites separating three layers of corner-sharing octahedra. The structure is discussed in comparison with the related eight-layer Ba8ZnTa6C24, which involves the (hccc) 2 stacking sequence, discovered in an earlier study. The microwave dielectric properties of both materials are determined (Ba10Mg 0.25Ta7.9O30 Qf = 33 585 at 4.02 GHz, εr = 28, and a temperature coefficient of resonant frequency τf = 30.2 ppm/°C; Ba10Co0.25Ta 7.9O30 Qf = 36 693 at 3.78 GHz, Tau;r = 30, τf = 28.6 ppm/°C), and factors controlling dielectric behavior in hexagonal perovskites are identified from the available structural and property data.
AB - The new ceramic materials Ba10Mg0.25Ta 7.9O30 and Ba10Co0.25Ta 7.9O30 have been synthesized in isolation and their dielectric and crystallographic properties characterized fully. The crystal structure determination, using a combination of X-ray and neutron powder diffraction and electron microscopy, reveals a 10-layer perovskite structure that involves the (hcccc)2 stacking sequence with a pair of face-sharing octahedral sites separating three layers of corner-sharing octahedra. The structure is discussed in comparison with the related eight-layer Ba8ZnTa6C24, which involves the (hccc) 2 stacking sequence, discovered in an earlier study. The microwave dielectric properties of both materials are determined (Ba10Mg 0.25Ta7.9O30 Qf = 33 585 at 4.02 GHz, εr = 28, and a temperature coefficient of resonant frequency τf = 30.2 ppm/°C; Ba10Co0.25Ta 7.9O30 Qf = 36 693 at 3.78 GHz, Tau;r = 30, τf = 28.6 ppm/°C), and factors controlling dielectric behavior in hexagonal perovskites are identified from the available structural and property data.
UR - http://www.scopus.com/inward/record.url?scp=33846372916&partnerID=8YFLogxK
U2 - 10.1021/cm0616477
DO - 10.1021/cm0616477
M3 - Article
AN - SCOPUS:33846372916
SN - 0897-4756
VL - 18
SP - 6227
EP - 6238
JO - Chemistry of Materials
JF - Chemistry of Materials
IS - 26
ER -