自組裝的鈣鈦礦-尖晶石系統中異質磊晶的奈米結構方向控制

Abstract

本實驗經由選擇不同的基版來控制自組裝奈米結構的晶體方向與磁性質。在perovskit-spinel BiFeO3-CoFe2O4複合薄膜系統中，在固定BiFeO3基底為(001)情況下，自組裝奈米柱CoFe2O4的方向可調控為(001)、(011)或(111)。不同方向的奈米柱CoFe2O4的形狀也呈現不同的樣示：金字塔形、屋頂形、三角平台形。也由於CoFe2O4有磁的異向性，不同型態的複合薄膜表現了不同的磁性質。這個研究於自組裝異質成核的奈米結構中開闢了新的可能。

In this study, advanced control of crystallographic orientations and magnetic properties of self-assembled nanostructures via rational selections of substrates are demonstrated. We show that in the perovskite-spinel BiFeO3-CoFe2O4 model system the crystal orientation of self-assembled CoFe2O4 nanopillars can be tuned among (001), (011), and (111) while that of BiFeO3 matrix is fixed in (001). Moreover, the resultant CoFe2O4 nanopillars appear in various shapes: pyramid, roof, and triangular platform respectively. The tunable nanostructures through this approach enable the control over material functionality such as the magnetic anisotropy of CoFe2O4. This study opens a new pathway for engineering of self-assembled hetero-epitaxial nanostructures.