摘要
采用变温ＦＴＲａｍａｎ技术测定了三种粒径Ｐｂ０．８５Ｃａ０．１５ＴｉＯ３纳米晶的居里温度。１７８９ｎｍ、２５．６９ｎｍ、和３６２５ｎｍ粒子的Ｔｃ分别为２７４℃，２６５℃，２９４℃。认为尺寸效应和掺杂引起的缺陷均对Ｔｃ产生影响。掺杂及焙烧不充分引起的晶体缺陷使居里点弥散。
FT Raman spectra of Pb 0.85 Ca 0.15 TiO 3 nanocrystals with different grain sizes were measured from room temperature to past the Curie temperature (T c). to determine the Curie temperature of sample. T c was found to be 274℃, 265℃, and 294℃ for grain size of 17.89nm, 25.69nm, and 36.25nm respectively. The result indicates that both doping effect and size effect can influence T c. Defects in the nanocrystals from doping or insufficient calcination lead to a more diffused T c. At the same time, the E(1TO) soft mode shows a typical underdamp characteristic.
出处
《光散射学报》
1999年第2期123-126,共4页
The Journal of Light Scattering
基金
黑龙江省自然科学基金
黑龙江大学杰出青年科学基金
关键词
钙改性
钛酸铅
纳米晶
铁电顺电相变
拉曼光谱
calcium modified lead titanate
nanocrystal
ferroelectric paraelectric phase transition
FT Raman
curie temperature(T c)
