Development and Manufacturing of Maltilayer coated Ceramic-Composite Particles.

本研究的目的是借由在薄膜与基板之间引入缓冲层，以达到控制残余应力的类单晶薄膜。从薄膜与衬底的晶格失配和热膨胀系数差异出发，选择了几种不同成分或成分梯度的缓冲层，研究了残余应力对薄膜电学性能的影响，测量了沉积在（100）SrTiO_3基片上的（001）PbTiO_3薄膜在不同残余应力下的电学性能。残余应力的变化是由薄膜沉积后的基板的机械减薄或基板的机械弯曲。随着薄膜面内拉应力的增加，PbTiO_3薄膜的剩余极化强度和矫顽场逐渐减小，通过引入不同的抛光剂，可以有效地控制薄膜的残余应力 ...更多信息 在（001）Pb（Zr，Ti）O_3薄膜和（100）SrTiO_3衬底之间生长了两层多层膜。采用PbTiO_3和PbTiO_3→Pb（Zr，Ti）O_3或PbZrO_3→Pb（Zr，Ti）O_3组成梯度薄膜作为缓冲层。由于Pb（Zr，Ti）O_3、缓冲层和SrTiO_3之间的晶格失配很小，与热膨胀系数差的影响相比，晶格失配的影响可以忽略不计。通过引入热膨胀系数比SrTiO_3和Pb（Zr，Ti）O_3大的缓冲层（如PbTiO_3或PbTiO_3→Pb（Zr，Ti）O_3），可以缓解Pb（Zr，Ti）O_3薄膜的面内张应力。相反，热膨胀系数较小的缓冲层如PbZrO_3→Pb（Zr，Ti）O_3使面内张应力增大，由此我们试图通过引入缓冲层来改变电学性能。在（001）PbTiO_3外延膜和（100）SrTiO_3衬底之间引入不同PbTiO_3厚度的Pt/PbTiO_3缓冲层，实现Pt/PbTiO_3 /Pt/PbTiO_3缓冲/SrTiO_3。随着PbTiO_3缓冲层厚度的增加，面内拉应力减小，剩余极化强度增加。少

The purpose of this study is to realize the single crystal like thin films with controlled residual stress by introducing the buffer layer between thin film and substrate. Several kinds of buffer layers with different composition or compositionally gradient were chosen at the standing points of the lattice mismatch and the thermal expansion coefficient difference between the thin film and the substrate.To clarify the effects of residual stress on the electrical properties of the thin film, the electrical properties of the (001) PbTiO_3 thin film deposited on the (100) SrTiO_3 substrates with different residual stresses were measured. The residual stress was changed by the mechanical thinning of the substrate after thin film deposition or mechanical bending of the substrate. Increasing the inplane tensile stress of the thin film, the remnant polarization and the coercive field of the PbTiO_3 were decreasing.The residual stress was successively controlled by introducing the various buffe … More r layers between epitaxially grown (001)Pb(Zr, Ti)O_3 thin film and (100) SrTiO_3 substrate. PbTiO_3 and compositionally gradient films with PbTiO_3→Pb(Zr, Ti)O_3 or PbZrO_3→Pb(Zr, Ti)O_3 were used as buffer layers. Since lattice mismatch among Pb(Zr, Ti)O_3, buffer layer and SrTiO_3 is rather small in this system, the effect of the lattice mismatch might be negligible compared with the effect of thermal expansion coefficient differences. Introducing the buffer layers with higher thermal expansion coefficient than SrTiO_3 and Pb(Zr, Ti)O_3 such as PbTiO_3 or PbTiO_3→Pb(Zr, Ti)O_3, the in-plane tensile stress of the Pb(Zr, Ti) O_3 film was relaxing. In contrast, the buffer layer with lower thermal expansion coefficient such as PbZrO_3→Pb(Zr, Ti)O_3 extended the in-plane tensile stress.From these results we tried to change the electrical properties by introducing the buffer layer. Pt/PbTiO_3 buffer layers with different PbTiO_3 thickness were introduced between epitaxial (001)PbTiO_3 film and (100)SrTiO_3 substrate to realize Pt/PbTiO_3 /Pt/PbTiO_3 buffer/SrTiO_3. Increasing the thickness of the PbTiO_3 buffer, the remnant polarization was increasing by decreasing the in-plane tensile stress. Less