Nanometer-scale separation of d(10) Zn2+-layers and twin-shift   competition in Ba8ZnNb6O24-based 8-layered hexagonal perovskites

doi:10.1039/c5dt00859j

CORC > 北京大学 > 化学与分子工程学院

	Nanometer-scale separation of d(10) Zn2+-layers and twin-shift competition in Ba8ZnNb6O24-based 8-layered hexagonal perovskites
	Lu, Fengqi ; Wang, Xiaoming ; Pan, Zhengwei ; Pan, Fengjuan ; Chai, Shiqiang ; Liang, Chaolun ; Wang, Quanchao ; Wang, Jing ; Fang, Liang ; Kuang, Xiaojun ; Jing, Xiping
刊名	DALTON TRANSACTIONS
	2015
关键词	MICROWAVE DIELECTRIC-PROPERTIES POWDER NEUTRON-DIFFRACTION CRYSTAL-STRUCTURE METAL-OXIDES STRUCTURE REFINEMENT PROFILE REFINEMENT PHASE-TRANSITIONS SOLID-SOLUTIONS CATION CERAMICS
DOI	10.1039/c5dt00859j
英文摘要	The 8-layered shifted hexagonal perovskite compound Ba8ZnNb6O24 was isolated via controlling the ZnO volatilization, which features long-range B-cation ordering with nanometer-scale separation by similar to 1.9 nm of octahedral d(10) cationic (Zn2+) layers within the purely corner-sharing octahedral d(0) cationic (Nb5+) host. The long-range ordering of the B-site vacancy and out-of-center distortion of the highly-charged d(0) Nb5+ that is assisted by the second-order Jahn-Teller effect contribute to this unusual B-cation ordering in Ba8ZnNb6O24. A small amount (similar to 15%) of d(10) Sb5+ substitution for Nb5+ in Ba8ZnNb6-xSbxO24 dramatically transformed the shifted structure to a twinned structure, in contrast with the Ba8ZnNb6-xTaxO24 case requiring 50% d(0) Ta5+ substitution for Nb5+ for such a shift-to-twin transformation. Multiple factors including B-cationic sizes, electrostatic repulsion forces, long-range ordering of B-site vacancies, and bonding preferences arising from a covalent contribution to the B-O bonding that includes out-ofcenter octahedral distortion and the B-O-B bonding angle could subtly contribute to the twin-shift phase competition of B-site deficient 8-layered hexagonal perovskites Ba8B7O24. The ceramics of new shifted Ba8ZnNb6O24 and twinned Ba8ZnNb5.1Sb0.9O24 compounds exhibited good microwave dielectric properties (epsilon(r) similar to 35, Qf similar to 36 200-43 400 GHz and tau(f) similar to 38-44 ppm/degrees C).; National Natural Science Foundation of China [21361008]; Guangdong Natural Science Foundation [S2011010001310]; Guangxi Program for Hundred Talents for Returned Scholars; Guangxi Key Laboratory for Advanced Materials and New Preparation Technology [12AA-11]; Bragg Institute of the Australian Nuclear Science and Technology Organisation (ANSTO); SCI(E); EI; ARTICLE; kuangxj@gult.edu.cn; xpjing@pku.edu.cn; 29; 13173-13185; 44
语种	中文
内容类型	期刊论文
源URL	[http://ir.pku.edu.cn/handle/20.500.11897/421149]
专题	化学与分子工程学院
推荐引用方式 GB/T 7714	Lu, Fengqi,Wang, Xiaoming,Pan, Zhengwei,et al. Nanometer-scale separation of d(10) Zn2+-layers and twin-shift competition in Ba8ZnNb6O24-based 8-layered hexagonal perovskites[J]. DALTON TRANSACTIONS,2015.
APA	Lu, Fengqi.,Wang, Xiaoming.,Pan, Zhengwei.,Pan, Fengjuan.,Chai, Shiqiang.,...&Jing, Xiping.(2015).Nanometer-scale separation of d(10) Zn2+-layers and twin-shift competition in Ba8ZnNb6O24-based 8-layered hexagonal perovskites.DALTON TRANSACTIONS.
MLA	Lu, Fengqi,et al."Nanometer-scale separation of d(10) Zn2+-layers and twin-shift competition in Ba8ZnNb6O24-based 8-layered hexagonal perovskites".DALTON TRANSACTIONS (2015).