TY - JOUR
T1 - Room temperature electromechanical and magnetic investigations of ferroelectric Aurivillius phase Bi5Ti3(FexMn1-x)O-15 (x=1 and 0.7) chemical solution deposited thin films
AU - Whatmore, Roger
AU - Keeney, Lynette
AU - Groh, Claudia
AU - Kulkarni, Santosh
AU - Roy, Saibal
AU - Pemble, Martyn E.
PY - 2012/7/15
Y1 - 2012/7/15
N2 - Aurivillius phase thin films of Bi 5Ti 3(Fe xMn 1-x)O 15 with x 1 (Bi 5Ti 3FeO 15) and 0.7 (Bi 5Ti 3Fe 0.7Mn 0.3O 15) on SiO 2-Si(100) and Pt/Ti/SiO 2-Si substrates were fabricated by chemical solution deposition. The method was optimized in order to suppress formation of pyrochlore phase Bi 2Ti 2O 7 and improve crystallinity. The structural properties of the films were examined by x-ray diffraction, scanning electron microscopy, and atomic force microscopy. Optimum crystallinity and pyrochlore phase suppression was achieved by the addition of 15 to 25 mol. excess bismuth to the sols. Based on this study, 17.5 mol. excess bismuth was used in the preparation of Bi 2Ti 2O 7-free films of Bi 5Ti 3FeO 15 on SrTiO 3(100) and NdGaO 3(001) substrates, confirming the suppression of pyrochlore phase using this excess of bismuth. Thirty percent of the Fe 3 ions in Bi 5Ti 3FeO 15 was substituted with Mn 3 ions to form Bi 2Ti 2O 7-free thin films of Bi 5Ti 3Fe 0.7Mn 0.3O 15 on Pt/Ti/SiO 2-Si, SiO 2-Si(100), SrTiO 3(100), and NdGaO 3(001) substrates. Bi 5Ti 3FeO 15 and Bi 5Ti 3Fe 0.7Mn 0.3O 15 thin films on Pt/Ti/SiO 2-Si and SiO 2-Si(100) substrates were achieved with a higher degree of a-axis orientation compared with the films on SrTiO 3(100) and NdGaO 3(001) substrates. Room temperature electromechanical and magnetic properties of the thin films were investigated in order to assess the potential of these materials for piezoelectric, ferroelectric, and multiferroic applications. Vertical piezoresponse force microscopy measurements of the films demonstrate that Bi 5Ti 3FeO 15 and Bi 5Ti 3Fe 0.7Mn 0.3O 15 thin films are piezoelectric at room temperature. Room temperature switching spectroscopy-piezoresponse force microscopy measurements in the presence and absence of an applied bias demonstrate local ferroelectric switching behaviour (180°) in the films. Superconducting quantum interference device magnetometry measurements do not show any room temperature ferromagnetic hysteresis down to an upper detection limit of 2.53 × 10 -3 emu; and it is concluded, therefore, that such films are not mutiferroic at room temperature. Piezoresponse force microscopy lithography images of Bi 5Ti 3Fe 0.7Mn 0.3O 15 thin films are presented.
AB - Aurivillius phase thin films of Bi 5Ti 3(Fe xMn 1-x)O 15 with x 1 (Bi 5Ti 3FeO 15) and 0.7 (Bi 5Ti 3Fe 0.7Mn 0.3O 15) on SiO 2-Si(100) and Pt/Ti/SiO 2-Si substrates were fabricated by chemical solution deposition. The method was optimized in order to suppress formation of pyrochlore phase Bi 2Ti 2O 7 and improve crystallinity. The structural properties of the films were examined by x-ray diffraction, scanning electron microscopy, and atomic force microscopy. Optimum crystallinity and pyrochlore phase suppression was achieved by the addition of 15 to 25 mol. excess bismuth to the sols. Based on this study, 17.5 mol. excess bismuth was used in the preparation of Bi 2Ti 2O 7-free films of Bi 5Ti 3FeO 15 on SrTiO 3(100) and NdGaO 3(001) substrates, confirming the suppression of pyrochlore phase using this excess of bismuth. Thirty percent of the Fe 3 ions in Bi 5Ti 3FeO 15 was substituted with Mn 3 ions to form Bi 2Ti 2O 7-free thin films of Bi 5Ti 3Fe 0.7Mn 0.3O 15 on Pt/Ti/SiO 2-Si, SiO 2-Si(100), SrTiO 3(100), and NdGaO 3(001) substrates. Bi 5Ti 3FeO 15 and Bi 5Ti 3Fe 0.7Mn 0.3O 15 thin films on Pt/Ti/SiO 2-Si and SiO 2-Si(100) substrates were achieved with a higher degree of a-axis orientation compared with the films on SrTiO 3(100) and NdGaO 3(001) substrates. Room temperature electromechanical and magnetic properties of the thin films were investigated in order to assess the potential of these materials for piezoelectric, ferroelectric, and multiferroic applications. Vertical piezoresponse force microscopy measurements of the films demonstrate that Bi 5Ti 3FeO 15 and Bi 5Ti 3Fe 0.7Mn 0.3O 15 thin films are piezoelectric at room temperature. Room temperature switching spectroscopy-piezoresponse force microscopy measurements in the presence and absence of an applied bias demonstrate local ferroelectric switching behaviour (180°) in the films. Superconducting quantum interference device magnetometry measurements do not show any room temperature ferromagnetic hysteresis down to an upper detection limit of 2.53 × 10 -3 emu; and it is concluded, therefore, that such films are not mutiferroic at room temperature. Piezoresponse force microscopy lithography images of Bi 5Ti 3Fe 0.7Mn 0.3O 15 thin films are presented.
UR - https://www.scopus.com/pages/publications/84865471821
M3 - Article
AN - SCOPUS:84865471821
SN - 0021-8979
VL - 112
JO - Journal of Applied Physics
JF - Journal of Applied Physics
IS - 22
M1 - 024101
ER -