TY - JOUR
T1 - Pulsed-Laser Deposited 35 Bi(Mg1/2Ti1/2) O3-65 PbTiO3 Thin Films - Part I
T2 - Influence of Processing on Composition, Microstructure, and Ferroelectric Hysteresis
AU - Morandi, Carl
AU - Gray, Jennifer L.
AU - Auker, Wes
AU - Trolier-Mckinstry, Susan
N1 - Funding Information:
Manuscript received December 10, 2017; accepted April 3, 2018. Date of publication April 9, 2018; date of current version August 29, 2018. This work was supported by Texas Instruments. (Corresponding author: Carl Morandi.) C. Morandi and S. Trolier-McKinstry are with the Materials Science and Engineering Department and Materials Research Institute, Pennsylvania State University, University Park, PA 16802 USA (e-mail: csm204@psu.edu; set1@psu.edu).
Publisher Copyright:
© 1986-2012 IEEE.
PY - 2018/9
Y1 - 2018/9
N2 - 35 Bi(Mg1/2Ti1/2)O3 - 65 PbTiO3 (35 BiMT-65 PT) is a potential candidate material for a high-temperature nonvolatile ferroelectric memory. For pulsed-laser deposited 35 BiMT-65 PT films with the perovskite structure, it was found that as the chamber pressure during deposition decreased, the Mg and Pb contents in as-deposited films drop, while the concentration of Bi increases. Concurrently with the change in composition, the remanent polarization P-r increases 64% to ≈ 21μ C /cm2 and the polarization-electric field loops rotated counterclockwise as the deposition pressure increases. Decreasing the seed layer thickness from 36 to 16 nm led to a decrease in P-r to ≈ 14μ C /cm2. Adjusting the target composition allowed the deposition of films which had near-stoichiometric Bi and Mg concentrations, but in all cases, the grown films were lead deficient. These films had remanent polarizations of 18- 20μC/cm2. If the lead content of the target was increased too far, the remanent polarization decreased, possibly due to the need to evolve more PbO from defective growth layers. Finally, the deposition rate showed no substantial effect on the film composition, but did have a significant impact on the ferroelectric properties. As the deposition rate decreased, the P-r increased to ≈ 22μ C /cm2 due to enhanced crystalline quality. At laser frequencies of 5 Hz, a Mg-rich pyrochlore phase begins to form and films showed a maximum P-r≈ 22μC/cm2. The processing-composition behavior is explained via preferential adsorption of Bi on the A-site, which results in lead vacancies.
AB - 35 Bi(Mg1/2Ti1/2)O3 - 65 PbTiO3 (35 BiMT-65 PT) is a potential candidate material for a high-temperature nonvolatile ferroelectric memory. For pulsed-laser deposited 35 BiMT-65 PT films with the perovskite structure, it was found that as the chamber pressure during deposition decreased, the Mg and Pb contents in as-deposited films drop, while the concentration of Bi increases. Concurrently with the change in composition, the remanent polarization P-r increases 64% to ≈ 21μ C /cm2 and the polarization-electric field loops rotated counterclockwise as the deposition pressure increases. Decreasing the seed layer thickness from 36 to 16 nm led to a decrease in P-r to ≈ 14μ C /cm2. Adjusting the target composition allowed the deposition of films which had near-stoichiometric Bi and Mg concentrations, but in all cases, the grown films were lead deficient. These films had remanent polarizations of 18- 20μC/cm2. If the lead content of the target was increased too far, the remanent polarization decreased, possibly due to the need to evolve more PbO from defective growth layers. Finally, the deposition rate showed no substantial effect on the film composition, but did have a significant impact on the ferroelectric properties. As the deposition rate decreased, the P-r increased to ≈ 22μ C /cm2 due to enhanced crystalline quality. At laser frequencies of 5 Hz, a Mg-rich pyrochlore phase begins to form and films showed a maximum P-r≈ 22μC/cm2. The processing-composition behavior is explained via preferential adsorption of Bi on the A-site, which results in lead vacancies.
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U2 - 10.1109/TUFFC.2018.2824979
DO - 10.1109/TUFFC.2018.2824979
M3 - Article
C2 - 29993827
AN - SCOPUS:85045186388
SN - 0885-3010
VL - 65
SP - 1525
EP - 1533
JO - IEEE Transactions on Ultrasonics, Ferroelectrics, and Frequency Control
JF - IEEE Transactions on Ultrasonics, Ferroelectrics, and Frequency Control
IS - 9
M1 - 8334249
ER -