最近因為新冠肺炎，氣溶膠這個名詞火遍了大江南北。
什麼是氣溶膠？
氣溶膠是指懸浮在氣體介質中的固態或液態顆粒所組成的氣態分散系統。當含有病毒的飛沫在空氣中懸浮，並逐漸失去水分，剩下的蛋白質和病原體組成核，就形成了飛沫核。
其實溶膠體系是個大家族，除了氣溶膠、還有以液體為分散介質的溶膠、以固體為分散介質的固溶膠。而溶膠—凝膠法，作為一種新型製備方法，在材料研究領域得到了廣泛應用。
清華大學李敬鋒教授研究團隊採用溶膠凝膠法制備了Sm摻雜鐵酸鉍(001)外延薄膜並研究了它的鐵電疇和相變，發表在Journal of Materiomics第4卷第1期。查看全文可訪問https://www.sciencedirect.com/science/article/pii/S2352847817300631#!
倒易空間圖和透射電鏡照片；不同溫度下最大壓電響應的變化
內容簡介：
BiFeO3, a room-temperature multiferroic material, has recently been increasingly applied as a potential lead-free piezoelectric material due to its large piezoelectricity achieved by doping.
由於通過摻雜能取得較高的壓電性能，室溫多鐵材料鐵酸鉍BiFeO3近來被越來越多作為有潛力的無鉛壓電材料而被應用。
In this work, 12% Sm-doped BiFeO3 epitaxial thin films were fabricated on Nb-doped SrTiO3 (001) single crystal substrates via sol-gel method.
本工作通過溶膠凝膠法在（001）單晶摻鈮鈦酸鍶SrTiO3襯底上製備了摻雜12%Sm的BiFeO3外延薄膜。
The epitaxy was verified by reciprocal space mapping (RSM) and transmission electron microscope (TEM). The TEM results indicated the coexistence of R3c andPbam phases in the film.
通過倒易空間圖和透射電鏡確認了外延性。透射電鏡也確認了R3c和Pbam相在該薄膜中的共存。
The domains and piezoelectric properties from room temperature to 200 °C were characterized by piezoresponse force microscopy (PFM).
通過壓電力顯微鏡測試了薄膜從室溫到200℃的疇結構和壓電響應的變化。
Domains became active from 110 °C to 170 °C, and domain configurations changed obviously. A partially fading piezoresponse indicated the emergence of antiferroelectric Pbam. The in-situ domain analysis suggested that the phase transition was accompanied by domain wall motion. Switching spectroscopy PFM (SS-PFM) was further conducted to investigate the piezoresponse during the phase transition.
在110℃到170℃，疇變得非常活躍，疇結構發生明顯改變。部分消失的壓電響應說明了Pbam反鐵電相的出現。原位的疇分析說明了相轉變伴隨著疇壁的移動。極化翻轉譜壓電力顯微鏡進一步確認了相變時的壓電響應變化。
Anomalous responses were found in both ON and OFF states at 170 °C, and the film exhibits typical antiferroelectric behavior at 200 °C, implying that the completion of phase transition and structure turned to the Pbam phase.
在170℃，On和OFF狀態的測試中都出現了異常的響應，說明了相變的發生。而在200℃時薄膜表現出標準的反鐵電的響應，說明了相變的完成，薄膜結構完全轉變到Pbam相。
This work revealed the origin of the high piezoresponse of Sm-doped BiFeO3 thin films at the morphotropic phase boundary (MPB).
本工作揭示了處於準同型相界成分的Sm摻雜BiFeO3薄膜高壓電響應的起因。
在20°C, 80°C, 140°C 和200°C下,壓電力顯微鏡掃描結果
從20 °C到200 °C，薄膜變形量和疇區域的變化
從40 °C到230 °C，光功率熱分析結果
On和Off狀態下，從20 °C到200 °C的變形量和相
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關鍵字: 法在 透射電鏡 Transmission
