Suppression of ferroelectric phase-transition in niobates via solid solution formation
Suppression of ferroelectric phase-transition in niobates via solid solution formation
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DOI：
10.1016/j.matlet.2019.07.032
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发表时间：
2019-11
影响因子：
3
通讯作者：
S. Lanfredi;F. R. Praxedes;F. F. Ivashita-F.;A. Paesano;M. Nobre
中科院分区：
文献类型：
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作者：
S. Lanfredi;F. R. Praxedes;F. F. Ivashita-F.;A. Paesano;M. Nobre
利用x射线衍射、Mössbauer光谱和高温介电光谱等技术研究了ksr2nb5o15主体结构掺杂对相变型铁对电的抑制作用。采用高能铣削法制备了具有ttb型四方钨青铜结构的高晶单相掺铁铌酸盐陶瓷，化学计量量为KSr2(FeNb4)O15-δ。两种技术Rietveld方法和Mössbauer光谱都表明，Fe3+阳离子占据了TTB结构中铌八面体位置上的两个不同的八面体位置，称为Nb(1)和Nb(2)。在室温下，KSr2(FeNb4)O15-δ的介电常数值比KSr2Nb5O15的介电常数值高2倍。铁准相变的抑制与消光是极性特性击穿的函数。讨论了由固溶体形成引起的新的非极性空间群的发展。
Suppression of the phase-transition type ferro-paraelectric from doping of KSr2Nb5O15host-structure was investigated by set of techniques X-ray diffraction, Mössbauer spectroscopy and Dielectric spectroscopy at high temperature. High crystalline and single phase iron-doped niobate ceramic with Tetragonal Tungsten Bronze TTB-type structure, stoichiometry KSr2(FeNb4)O15-δ, was prepared by conventional technique using high energy milling. Both techniques Rietveld Method and Mössbauer spectroscopy showed that Fe3+cations occupy two different octahedral sites in the TTB structure on the niobium octahedral sites, termed as Nb(1) and Nb(2). At room temperature, the dielectric permittivity value of the KSr2(FeNb4)O15-δis two times higher than the permittivity values of the KSr2Nb5O15. The suppression with extinction of ferro-para phase-transition occurs as function of break-down of polar characteristic. New non-polar space group development stemming from solid solution formation is discussed.