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Hiroshi Funakubo - One of the best experts on this subject based on the ideXlab platform.
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Large irreversible non-180° domain switching after poling treatment in Pb(Zr, Ti)O3 films
Applied Physics Letters, 2016Co-Authors: Yoshitaka Ehara, Tomoaki Yamada, Takahiro Oikawa, Naoya Oshima, Shintaro Yasui, Takahisa Shiraishi, Yasuhiko Imai, Osami Sakata, Hiroshi FunakuboAbstract:(11 1¯)/(111)-oriented rhombohedral Pb(Zr0.65Ti0.35)O3 films with different domain fractions were epitaxially grown on various single crystals. The volume fraction of (111)-Polar-Axis oriented domains in as-deposited films, Vpol.(as-depo.), was controlled by selecting a single crystal substrate with a different thermal expansion coefficient. Applying an electric field, referred to as “poling treatment”, resulted in irreversible non-180° domain switching from the (11 1¯)-oriented domain (non-Polar-Axis) to the (111)-oriented domain (Polar-Axis), which was observed by synchrotron X-ray diffraction. Remanent Polarization (Pr) values were higher than those estimated using the proportional relationship with Vpol.(as-depo.). However, the experimental Pr values were in good agreement with the values estimated using the volume fraction of (111)-oriented domains after applying the poling treatment. In rhombohedral Pb(Zr0.65Ti0.35)O3 films, 30%−50% of the (11 1¯)-oriented domains switched irreversibly to (111)-orie...
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Polar-Axis-oriented crystal growth of tetragonal PZT films on stainless steel substrate using pseudo-perovskite nanosheet buffer layer
AIP Advances, 2015Co-Authors: Yoshiki Minemura, Daichi Ichinose, Kohei Nagasaka, Jin Woon Kim, Hiromi Shima, Ken Nishida, Takanori Kiguchi, Toyohiko J. Konno, Naoya Oshima, Hiroshi FunakuboAbstract:Lead zirconate titanate (PZT) film with Polar Axis orientation was grown on a SUS 316L stainless steel substrate with the help of a Ca2Nb3O10 nanosheet (ns-CN) layer that had a pseudo-perovskite-type crystal structure. The ns-CN buffer layer was supported on a platinized SUS 316L (Pt/SUS) substrate, followed by chemical solution deposition (CSD) of the PZT films with tetragonal symmetry (Zr/Ti =40/60). The PZT films consisting of c-domain, with [001]-Axis orientation of the perovskite unit cell, were deposited on the ns-CN/Pt/SUS substrate owing to (i) epitaxial lattice matching between the unit cell of PZT and substrate surface and (ii) in-plane thermal stress applied to the PZT film during cooling-down step of CSD procedure. The c-domain-oriented PZT film on ns-CN/Pt/SUS substrate exhibited enhanced remanent Polarization of approximately 52 μC/cm2 and lowered dielectric permittivity of approximately 230, which are superior to those of conventional PZT films with random crystal orientation and comparable to those of epitaxial PZT films grown on (100)SrRuO3//(100)SrTiO3 substrates.
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Spontaneous Polarization estimation from the soft mode in strain-free epitaxial Polar Axis-oriented Pb(Zr,Ti)O3 thick films with tetragonal symmetry
Applied Physics Letters, 2011Co-Authors: Yoshitaka Ehara, Takashi Iijima, Tomoaki Yamada, Satoru Utsugi, Mitsumasa Nakajima, Hiroki Taniguchi, Mitsuru Itoh, Hiroshi FunakuboAbstract:The ferroelectric property, crystal structure, and A1(1TO) soft mode of almost strain-free epitaxial Polar Axis-oriented tetragonal lead zirconate titanate thick films grown on CaF2 substrates were investigated by changing the Zr/(Zr+Ti) ratio and the temperature. The square of spontaneous Polarization (Ps), Ps2, monotonically increased as tetragonal distortion, (c/a)−1, increased where a and c are the lattice parameters of the films and as the square of frequency in A1(1TO), ω2[A1(1TO)], increased. Additionally, the relationships of Ps2, (c/a−1), and ω2[A1(1TO)] were experimentally obtained, which confirmed the Ps value obtained from (c/a−1) and ω[A1(1TO)] without direct Polarization measurements.
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Growth of Polar Axis oriented tetragonal Pb(Zr,Ti)O3 films on CaF2 substrates with transparent (La0.07Sr0.93)SnO3
Journal of Crystal Growth, 2010Co-Authors: Satoru Utsugi, Tomoaki Yamada, Hiroshi Funakubo, Yoshitaka Ehara, Hidenori Tanaka, Hiroshi UchidaAbstract:Epitaxial (La0.07Sr0.93)SnO3 [LSSO] films were deposited on CaF2 substrates by pulse laser deposition. The (1 0 0)c orientation of LSSO films was observed only on (1 1 0)CaF2, whereas (1 1 0)c orientation was found on (1 1 1)CaF2 and (1 0 0)CaF2. (0 0 1) Polar Axis oriented tetragonal Pb(Zr0.35Ti0.65)O3 films were grown on the fabricated (1 0 0)cLSSO∥(1 1 0)CaF2 by pulsed metal organic chemical vapor deposition. The (0 0 1)Pb(Zr0.35Ti0.65)O3∥(1 0 0)cLSSO∥(1 1 0)CaF2 stack structure exhibited about 70% transparency with an adsorption edge of approximately 330 nm.
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Crystal structure and electrical property comparisons of epitaxial Pb(Zr,Ti)O3 thick films grown on (100)CaF2 and (100)SrTiO3 substrates
Journal of Applied Physics, 2009Co-Authors: Takashi Fujisawa, Hiroshi Nakaki, Rikyu Ikariyama, Hitoshi Morioka, Tomoaki Yamada, Mutsuo Ishikawa, Hiroshi FunakuboAbstract:Epitaxial Pb(Zr,Ti)O3 (PZT) thick films of 2.0–3.0 μm thickness were grown at 600 °C on (100)cSrRuO3∥(100)SrTiO3 and (100)cSrRuO3∥(100)LaNiO3∥(100)CaF2 substrates by pulsed-metal organic chemical vapor deposition. All films showed (100) and/or (001) orientations with tetragonal symmetry. It was found that there is an almost linear relationship between the estimated thermal strain from the deposition temperature to the Curie temperature and the volume fraction of (001) orientation in the mixture of (100) and (001) orientations for the films on both substrates. Consequently, the perfectly (001)-oriented, i.e., Polar-Axis-oriented, PZT thick films were obtained on CaF2 with the Zr/(Zr+Ti) ratio from 0.20 to 0.40. Moreover, the lattice parameter of a- and c-axes and their ratio (c/a) of those Polar-Axis-oriented films were almost the same as the reported data for the powder, suggesting that the large strain is not remaining in those films. The relative dielectric constant (er) of the Polar-Axis-oriented Pb(Zr...
Keisuke Saito - One of the best experts on this subject based on the ideXlab platform.
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Thick Epitaxial Pb(Zr0.35,Ti0.65)O3 Films Grown on (100)CaF2 Substrates with Polar-Axis-Orientation
Applied Physics Express, 2008Co-Authors: Takashi Fujisawa, Hiroshi Nakaki, Rikyu Ikariyama, Hitoshi Morioka, Tomoaki Yamada, Keisuke Saito, Hiroshi FunakuboAbstract:(100)/(001)-oriented tetragonal Pb(Zr,Ti)O3 (PZT) films, which were thicker than 2 µm, were epitaxially grown on SrRuO3-covered (100)Si, (100)KTaO3, (100)SrTiO3, and (100)CaF2 substrates by metal organic chemical vapor deposition. The volume fraction of the (001)-orientation almost linearly increased as the thermal strain increased during the cooling process from the deposition temperature to the Curie temperature. Consequently, perfectly (001)-oriented, i.e., Polar-Axis-oriented, thick films were obtained on CaF2 substrates with a remanent Polarization of 71 µC/cm2. This approach to grow Polar-Axis-oriented PZT thick films enabled the intrinsic piezoelectricity of PZT itself to be clarified, and has potential in novel applications.
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spontaneous Polarization change with zr zr ti ratios in perfectly Polar Axis orientated epitaxial tetragonal pb zr ti o3 films
Applied Physics Letters, 2004Co-Authors: Hitoshi Morioka, Hiroshi Funakubo, Takahiro Oikawa, Shintaro Yokoyama, Keisuke SaitoAbstract:Epitaxial Pb(Zr,Ti)O3 (PZT) films 50 and 250nm thick with the Zr∕(Zr+Ti) ratio from 0.13 to 0.65 were grown on (100)cSrRuO3∕∕(100)SrTiO3 substrates at 540°C by pulsed-metalorganic chemical vapor deposition. The crystal orientation, lattice parameter, axial angle, and relative volume fraction of constituent domains were determined by high-resolution x-ray diffraction reciprocal space mapping. We grew (100) and∕or (001)-oriented epitaxial PZT films for the whole Zr∕(Zr+Ti) ratio. A tetragonal single phase was obtained for the Zr∕(Zr+Ti) ratio ranging from 0.13 to 0.54 and 0.19 to 0.45 with the 50 and 250nm thick films, respectively, while mixed phases of a tetragonal and rhombohedral from 0.45 to 0.60 for the 250nm thick films was obtained. For the films consisting of a tetragonal single phase, lattice parameters of a- and c-axes and their ratio (c∕a) were almost the same as the reported data for the PZT powder, suggesting a small amount of residual strain in them. In addition, perfectly Polar-Axis (c-Axis)...
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Spontaneous Polarization change with Zr∕(Zr+Ti) ratios in perfectly Polar-Axis-orientated epitaxial tetragonal Pb(Zr,Ti)O3 films
Applied Physics Letters, 2004Co-Authors: Hitoshi Morioka, Hiroshi Funakubo, Takahiro Oikawa, Shintaro Yokoyama, Keisuke SaitoAbstract:Epitaxial Pb(Zr,Ti)O3 (PZT) films 50 and 250nm thick with the Zr∕(Zr+Ti) ratio from 0.13 to 0.65 were grown on (100)cSrRuO3∕∕(100)SrTiO3 substrates at 540°C by pulsed-metalorganic chemical vapor deposition. The crystal orientation, lattice parameter, axial angle, and relative volume fraction of constituent domains were determined by high-resolution x-ray diffraction reciprocal space mapping. We grew (100) and∕or (001)-oriented epitaxial PZT films for the whole Zr∕(Zr+Ti) ratio. A tetragonal single phase was obtained for the Zr∕(Zr+Ti) ratio ranging from 0.13 to 0.54 and 0.19 to 0.45 with the 50 and 250nm thick films, respectively, while mixed phases of a tetragonal and rhombohedral from 0.45 to 0.60 for the 250nm thick films was obtained. For the films consisting of a tetragonal single phase, lattice parameters of a- and c-axes and their ratio (c∕a) were almost the same as the reported data for the PZT powder, suggesting a small amount of residual strain in them. In addition, perfectly Polar-Axis (c-Axis)...
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Large remanent Polarization of 100% Polar-Axis-oriented epitaxial tetragonal Pb(Zr0.35Ti0.65)O3 thin films
Applied Physics Letters, 2003Co-Authors: Hitoshi Morioka, Hiroshi Funakubo, Gouji Asano, Takahiro Oikawa, Keisuke SaitoAbstract:100% Polar-Axis (c-Axis)-oriented epitaxial Pb(Zr0.35Ti0.65)O3 (PZT) thin films were grown and their large remanent Polarization (Pr) was directly measured. Perfectly c-Axis-oriented epitaxial PZT thin films were obtained on (100)cSrRuO3//(100)SrTiO3 substrates when the deposition temperature increased to 540 °C together with a decrease in the film thickness down to 50 nm. Polarization–electric-field hysteresis loops were well saturated and had a square shape. The Pr of a 50 nm thick film saturated at 0.9 V, and its value was over 90 μC/cm2; almost independent of the measurement frequency within the range from 20 Hz to 1 kHz. This value was in good agreement with the estimated one from the a- and c-axes mixture-oriented epitaxial PZT film having the same composition taking into account the fact that only the c-Axis-oriented domain contributed to the Polarization. On the other hand, the coercive field value of a perfectly c-Axis-oriented film was 140 kV/cm and almost the same as that of the mixture-oriente...
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large remanent Polarization of 100 Polar Axis oriented epitaxial tetragonal pb zr0 35ti0 65 o3 thin films
Applied Physics Letters, 2003Co-Authors: Hitoshi Morioka, Hiroshi Funakubo, Gouji Asano, Takahiro Oikawa, Keisuke SaitoAbstract:100% Polar-Axis (c-Axis)-oriented epitaxial Pb(Zr0.35Ti0.65)O3 (PZT) thin films were grown and their large remanent Polarization (Pr) was directly measured. Perfectly c-Axis-oriented epitaxial PZT thin films were obtained on (100)cSrRuO3//(100)SrTiO3 substrates when the deposition temperature increased to 540 °C together with a decrease in the film thickness down to 50 nm. Polarization–electric-field hysteresis loops were well saturated and had a square shape. The Pr of a 50 nm thick film saturated at 0.9 V, and its value was over 90 μC/cm2; almost independent of the measurement frequency within the range from 20 Hz to 1 kHz. This value was in good agreement with the estimated one from the a- and c-axes mixture-oriented epitaxial PZT film having the same composition taking into account the fact that only the c-Axis-oriented domain contributed to the Polarization. On the other hand, the coercive field value of a perfectly c-Axis-oriented film was 140 kV/cm and almost the same as that of the mixture-oriente...
Hitoshi Morioka - One of the best experts on this subject based on the ideXlab platform.
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Crystal structure and electrical property comparisons of epitaxial Pb(Zr,Ti)O3 thick films grown on (100)CaF2 and (100)SrTiO3 substrates
Journal of Applied Physics, 2009Co-Authors: Takashi Fujisawa, Hiroshi Nakaki, Rikyu Ikariyama, Hitoshi Morioka, Tomoaki Yamada, Mutsuo Ishikawa, Hiroshi FunakuboAbstract:Epitaxial Pb(Zr,Ti)O3 (PZT) thick films of 2.0–3.0 μm thickness were grown at 600 °C on (100)cSrRuO3∥(100)SrTiO3 and (100)cSrRuO3∥(100)LaNiO3∥(100)CaF2 substrates by pulsed-metal organic chemical vapor deposition. All films showed (100) and/or (001) orientations with tetragonal symmetry. It was found that there is an almost linear relationship between the estimated thermal strain from the deposition temperature to the Curie temperature and the volume fraction of (001) orientation in the mixture of (100) and (001) orientations for the films on both substrates. Consequently, the perfectly (001)-oriented, i.e., Polar-Axis-oriented, PZT thick films were obtained on CaF2 with the Zr/(Zr+Ti) ratio from 0.20 to 0.40. Moreover, the lattice parameter of a- and c-axes and their ratio (c/a) of those Polar-Axis-oriented films were almost the same as the reported data for the powder, suggesting that the large strain is not remaining in those films. The relative dielectric constant (er) of the Polar-Axis-oriented Pb(Zr...
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Thick Epitaxial Pb(Zr0.35,Ti0.65)O3 Films Grown on (100)CaF2 Substrates with Polar-Axis-Orientation
Applied Physics Express, 2008Co-Authors: Takashi Fujisawa, Hiroshi Nakaki, Rikyu Ikariyama, Hitoshi Morioka, Tomoaki Yamada, Keisuke Saito, Hiroshi FunakuboAbstract:(100)/(001)-oriented tetragonal Pb(Zr,Ti)O3 (PZT) films, which were thicker than 2 µm, were epitaxially grown on SrRuO3-covered (100)Si, (100)KTaO3, (100)SrTiO3, and (100)CaF2 substrates by metal organic chemical vapor deposition. The volume fraction of the (001)-orientation almost linearly increased as the thermal strain increased during the cooling process from the deposition temperature to the Curie temperature. Consequently, perfectly (001)-oriented, i.e., Polar-Axis-oriented, thick films were obtained on CaF2 substrates with a remanent Polarization of 71 µC/cm2. This approach to grow Polar-Axis-oriented PZT thick films enabled the intrinsic piezoelectricity of PZT itself to be clarified, and has potential in novel applications.
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spontaneous Polarization change with zr zr ti ratios in perfectly Polar Axis orientated epitaxial tetragonal pb zr ti o3 films
Applied Physics Letters, 2004Co-Authors: Hitoshi Morioka, Hiroshi Funakubo, Takahiro Oikawa, Shintaro Yokoyama, Keisuke SaitoAbstract:Epitaxial Pb(Zr,Ti)O3 (PZT) films 50 and 250nm thick with the Zr∕(Zr+Ti) ratio from 0.13 to 0.65 were grown on (100)cSrRuO3∕∕(100)SrTiO3 substrates at 540°C by pulsed-metalorganic chemical vapor deposition. The crystal orientation, lattice parameter, axial angle, and relative volume fraction of constituent domains were determined by high-resolution x-ray diffraction reciprocal space mapping. We grew (100) and∕or (001)-oriented epitaxial PZT films for the whole Zr∕(Zr+Ti) ratio. A tetragonal single phase was obtained for the Zr∕(Zr+Ti) ratio ranging from 0.13 to 0.54 and 0.19 to 0.45 with the 50 and 250nm thick films, respectively, while mixed phases of a tetragonal and rhombohedral from 0.45 to 0.60 for the 250nm thick films was obtained. For the films consisting of a tetragonal single phase, lattice parameters of a- and c-axes and their ratio (c∕a) were almost the same as the reported data for the PZT powder, suggesting a small amount of residual strain in them. In addition, perfectly Polar-Axis (c-Axis)...
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Spontaneous Polarization change with Zr∕(Zr+Ti) ratios in perfectly Polar-Axis-orientated epitaxial tetragonal Pb(Zr,Ti)O3 films
Applied Physics Letters, 2004Co-Authors: Hitoshi Morioka, Hiroshi Funakubo, Takahiro Oikawa, Shintaro Yokoyama, Keisuke SaitoAbstract:Epitaxial Pb(Zr,Ti)O3 (PZT) films 50 and 250nm thick with the Zr∕(Zr+Ti) ratio from 0.13 to 0.65 were grown on (100)cSrRuO3∕∕(100)SrTiO3 substrates at 540°C by pulsed-metalorganic chemical vapor deposition. The crystal orientation, lattice parameter, axial angle, and relative volume fraction of constituent domains were determined by high-resolution x-ray diffraction reciprocal space mapping. We grew (100) and∕or (001)-oriented epitaxial PZT films for the whole Zr∕(Zr+Ti) ratio. A tetragonal single phase was obtained for the Zr∕(Zr+Ti) ratio ranging from 0.13 to 0.54 and 0.19 to 0.45 with the 50 and 250nm thick films, respectively, while mixed phases of a tetragonal and rhombohedral from 0.45 to 0.60 for the 250nm thick films was obtained. For the films consisting of a tetragonal single phase, lattice parameters of a- and c-axes and their ratio (c∕a) were almost the same as the reported data for the PZT powder, suggesting a small amount of residual strain in them. In addition, perfectly Polar-Axis (c-Axis)...
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Large remanent Polarization of 100% Polar-Axis-oriented epitaxial tetragonal Pb(Zr0.35Ti0.65)O3 thin films
Applied Physics Letters, 2003Co-Authors: Hitoshi Morioka, Hiroshi Funakubo, Gouji Asano, Takahiro Oikawa, Keisuke SaitoAbstract:100% Polar-Axis (c-Axis)-oriented epitaxial Pb(Zr0.35Ti0.65)O3 (PZT) thin films were grown and their large remanent Polarization (Pr) was directly measured. Perfectly c-Axis-oriented epitaxial PZT thin films were obtained on (100)cSrRuO3//(100)SrTiO3 substrates when the deposition temperature increased to 540 °C together with a decrease in the film thickness down to 50 nm. Polarization–electric-field hysteresis loops were well saturated and had a square shape. The Pr of a 50 nm thick film saturated at 0.9 V, and its value was over 90 μC/cm2; almost independent of the measurement frequency within the range from 20 Hz to 1 kHz. This value was in good agreement with the estimated one from the a- and c-axes mixture-oriented epitaxial PZT film having the same composition taking into account the fact that only the c-Axis-oriented domain contributed to the Polarization. On the other hand, the coercive field value of a perfectly c-Axis-oriented film was 140 kV/cm and almost the same as that of the mixture-oriente...
Takahiro Oikawa - One of the best experts on this subject based on the ideXlab platform.
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Large irreversible non-180° domain switching after poling treatment in Pb(Zr, Ti)O3 films
Applied Physics Letters, 2016Co-Authors: Yoshitaka Ehara, Tomoaki Yamada, Takahiro Oikawa, Naoya Oshima, Shintaro Yasui, Takahisa Shiraishi, Yasuhiko Imai, Osami Sakata, Hiroshi FunakuboAbstract:(11 1¯)/(111)-oriented rhombohedral Pb(Zr0.65Ti0.35)O3 films with different domain fractions were epitaxially grown on various single crystals. The volume fraction of (111)-Polar-Axis oriented domains in as-deposited films, Vpol.(as-depo.), was controlled by selecting a single crystal substrate with a different thermal expansion coefficient. Applying an electric field, referred to as “poling treatment”, resulted in irreversible non-180° domain switching from the (11 1¯)-oriented domain (non-Polar-Axis) to the (111)-oriented domain (Polar-Axis), which was observed by synchrotron X-ray diffraction. Remanent Polarization (Pr) values were higher than those estimated using the proportional relationship with Vpol.(as-depo.). However, the experimental Pr values were in good agreement with the values estimated using the volume fraction of (111)-oriented domains after applying the poling treatment. In rhombohedral Pb(Zr0.65Ti0.35)O3 films, 30%−50% of the (11 1¯)-oriented domains switched irreversibly to (111)-orie...
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spontaneous Polarization change with zr zr ti ratios in perfectly Polar Axis orientated epitaxial tetragonal pb zr ti o3 films
Applied Physics Letters, 2004Co-Authors: Hitoshi Morioka, Hiroshi Funakubo, Takahiro Oikawa, Shintaro Yokoyama, Keisuke SaitoAbstract:Epitaxial Pb(Zr,Ti)O3 (PZT) films 50 and 250nm thick with the Zr∕(Zr+Ti) ratio from 0.13 to 0.65 were grown on (100)cSrRuO3∕∕(100)SrTiO3 substrates at 540°C by pulsed-metalorganic chemical vapor deposition. The crystal orientation, lattice parameter, axial angle, and relative volume fraction of constituent domains were determined by high-resolution x-ray diffraction reciprocal space mapping. We grew (100) and∕or (001)-oriented epitaxial PZT films for the whole Zr∕(Zr+Ti) ratio. A tetragonal single phase was obtained for the Zr∕(Zr+Ti) ratio ranging from 0.13 to 0.54 and 0.19 to 0.45 with the 50 and 250nm thick films, respectively, while mixed phases of a tetragonal and rhombohedral from 0.45 to 0.60 for the 250nm thick films was obtained. For the films consisting of a tetragonal single phase, lattice parameters of a- and c-axes and their ratio (c∕a) were almost the same as the reported data for the PZT powder, suggesting a small amount of residual strain in them. In addition, perfectly Polar-Axis (c-Axis)...
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Spontaneous Polarization change with Zr∕(Zr+Ti) ratios in perfectly Polar-Axis-orientated epitaxial tetragonal Pb(Zr,Ti)O3 films
Applied Physics Letters, 2004Co-Authors: Hitoshi Morioka, Hiroshi Funakubo, Takahiro Oikawa, Shintaro Yokoyama, Keisuke SaitoAbstract:Epitaxial Pb(Zr,Ti)O3 (PZT) films 50 and 250nm thick with the Zr∕(Zr+Ti) ratio from 0.13 to 0.65 were grown on (100)cSrRuO3∕∕(100)SrTiO3 substrates at 540°C by pulsed-metalorganic chemical vapor deposition. The crystal orientation, lattice parameter, axial angle, and relative volume fraction of constituent domains were determined by high-resolution x-ray diffraction reciprocal space mapping. We grew (100) and∕or (001)-oriented epitaxial PZT films for the whole Zr∕(Zr+Ti) ratio. A tetragonal single phase was obtained for the Zr∕(Zr+Ti) ratio ranging from 0.13 to 0.54 and 0.19 to 0.45 with the 50 and 250nm thick films, respectively, while mixed phases of a tetragonal and rhombohedral from 0.45 to 0.60 for the 250nm thick films was obtained. For the films consisting of a tetragonal single phase, lattice parameters of a- and c-axes and their ratio (c∕a) were almost the same as the reported data for the PZT powder, suggesting a small amount of residual strain in them. In addition, perfectly Polar-Axis (c-Axis)...
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Large remanent Polarization of 100% Polar-Axis-oriented epitaxial tetragonal Pb(Zr0.35Ti0.65)O3 thin films
Applied Physics Letters, 2003Co-Authors: Hitoshi Morioka, Hiroshi Funakubo, Gouji Asano, Takahiro Oikawa, Keisuke SaitoAbstract:100% Polar-Axis (c-Axis)-oriented epitaxial Pb(Zr0.35Ti0.65)O3 (PZT) thin films were grown and their large remanent Polarization (Pr) was directly measured. Perfectly c-Axis-oriented epitaxial PZT thin films were obtained on (100)cSrRuO3//(100)SrTiO3 substrates when the deposition temperature increased to 540 °C together with a decrease in the film thickness down to 50 nm. Polarization–electric-field hysteresis loops were well saturated and had a square shape. The Pr of a 50 nm thick film saturated at 0.9 V, and its value was over 90 μC/cm2; almost independent of the measurement frequency within the range from 20 Hz to 1 kHz. This value was in good agreement with the estimated one from the a- and c-axes mixture-oriented epitaxial PZT film having the same composition taking into account the fact that only the c-Axis-oriented domain contributed to the Polarization. On the other hand, the coercive field value of a perfectly c-Axis-oriented film was 140 kV/cm and almost the same as that of the mixture-oriente...
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large remanent Polarization of 100 Polar Axis oriented epitaxial tetragonal pb zr0 35ti0 65 o3 thin films
Applied Physics Letters, 2003Co-Authors: Hitoshi Morioka, Hiroshi Funakubo, Gouji Asano, Takahiro Oikawa, Keisuke SaitoAbstract:100% Polar-Axis (c-Axis)-oriented epitaxial Pb(Zr0.35Ti0.65)O3 (PZT) thin films were grown and their large remanent Polarization (Pr) was directly measured. Perfectly c-Axis-oriented epitaxial PZT thin films were obtained on (100)cSrRuO3//(100)SrTiO3 substrates when the deposition temperature increased to 540 °C together with a decrease in the film thickness down to 50 nm. Polarization–electric-field hysteresis loops were well saturated and had a square shape. The Pr of a 50 nm thick film saturated at 0.9 V, and its value was over 90 μC/cm2; almost independent of the measurement frequency within the range from 20 Hz to 1 kHz. This value was in good agreement with the estimated one from the a- and c-axes mixture-oriented epitaxial PZT film having the same composition taking into account the fact that only the c-Axis-oriented domain contributed to the Polarization. On the other hand, the coercive field value of a perfectly c-Axis-oriented film was 140 kV/cm and almost the same as that of the mixture-oriente...
Tomoaki Yamada - One of the best experts on this subject based on the ideXlab platform.
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Large irreversible non-180° domain switching after poling treatment in Pb(Zr, Ti)O3 films
Applied Physics Letters, 2016Co-Authors: Yoshitaka Ehara, Tomoaki Yamada, Takahiro Oikawa, Naoya Oshima, Shintaro Yasui, Takahisa Shiraishi, Yasuhiko Imai, Osami Sakata, Hiroshi FunakuboAbstract:(11 1¯)/(111)-oriented rhombohedral Pb(Zr0.65Ti0.35)O3 films with different domain fractions were epitaxially grown on various single crystals. The volume fraction of (111)-Polar-Axis oriented domains in as-deposited films, Vpol.(as-depo.), was controlled by selecting a single crystal substrate with a different thermal expansion coefficient. Applying an electric field, referred to as “poling treatment”, resulted in irreversible non-180° domain switching from the (11 1¯)-oriented domain (non-Polar-Axis) to the (111)-oriented domain (Polar-Axis), which was observed by synchrotron X-ray diffraction. Remanent Polarization (Pr) values were higher than those estimated using the proportional relationship with Vpol.(as-depo.). However, the experimental Pr values were in good agreement with the values estimated using the volume fraction of (111)-oriented domains after applying the poling treatment. In rhombohedral Pb(Zr0.65Ti0.35)O3 films, 30%−50% of the (11 1¯)-oriented domains switched irreversibly to (111)-orie...
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Spontaneous Polarization estimation from the soft mode in strain-free epitaxial Polar Axis-oriented Pb(Zr,Ti)O3 thick films with tetragonal symmetry
Applied Physics Letters, 2011Co-Authors: Yoshitaka Ehara, Takashi Iijima, Tomoaki Yamada, Satoru Utsugi, Mitsumasa Nakajima, Hiroki Taniguchi, Mitsuru Itoh, Hiroshi FunakuboAbstract:The ferroelectric property, crystal structure, and A1(1TO) soft mode of almost strain-free epitaxial Polar Axis-oriented tetragonal lead zirconate titanate thick films grown on CaF2 substrates were investigated by changing the Zr/(Zr+Ti) ratio and the temperature. The square of spontaneous Polarization (Ps), Ps2, monotonically increased as tetragonal distortion, (c/a)−1, increased where a and c are the lattice parameters of the films and as the square of frequency in A1(1TO), ω2[A1(1TO)], increased. Additionally, the relationships of Ps2, (c/a−1), and ω2[A1(1TO)] were experimentally obtained, which confirmed the Ps value obtained from (c/a−1) and ω[A1(1TO)] without direct Polarization measurements.
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Growth of Polar Axis oriented tetragonal Pb(Zr,Ti)O3 films on CaF2 substrates with transparent (La0.07Sr0.93)SnO3
Journal of Crystal Growth, 2010Co-Authors: Satoru Utsugi, Tomoaki Yamada, Hiroshi Funakubo, Yoshitaka Ehara, Hidenori Tanaka, Hiroshi UchidaAbstract:Epitaxial (La0.07Sr0.93)SnO3 [LSSO] films were deposited on CaF2 substrates by pulse laser deposition. The (1 0 0)c orientation of LSSO films was observed only on (1 1 0)CaF2, whereas (1 1 0)c orientation was found on (1 1 1)CaF2 and (1 0 0)CaF2. (0 0 1) Polar Axis oriented tetragonal Pb(Zr0.35Ti0.65)O3 films were grown on the fabricated (1 0 0)cLSSO∥(1 1 0)CaF2 by pulsed metal organic chemical vapor deposition. The (0 0 1)Pb(Zr0.35Ti0.65)O3∥(1 0 0)cLSSO∥(1 1 0)CaF2 stack structure exhibited about 70% transparency with an adsorption edge of approximately 330 nm.
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Crystal structure and electrical property comparisons of epitaxial Pb(Zr,Ti)O3 thick films grown on (100)CaF2 and (100)SrTiO3 substrates
Journal of Applied Physics, 2009Co-Authors: Takashi Fujisawa, Hiroshi Nakaki, Rikyu Ikariyama, Hitoshi Morioka, Tomoaki Yamada, Mutsuo Ishikawa, Hiroshi FunakuboAbstract:Epitaxial Pb(Zr,Ti)O3 (PZT) thick films of 2.0–3.0 μm thickness were grown at 600 °C on (100)cSrRuO3∥(100)SrTiO3 and (100)cSrRuO3∥(100)LaNiO3∥(100)CaF2 substrates by pulsed-metal organic chemical vapor deposition. All films showed (100) and/or (001) orientations with tetragonal symmetry. It was found that there is an almost linear relationship between the estimated thermal strain from the deposition temperature to the Curie temperature and the volume fraction of (001) orientation in the mixture of (100) and (001) orientations for the films on both substrates. Consequently, the perfectly (001)-oriented, i.e., Polar-Axis-oriented, PZT thick films were obtained on CaF2 with the Zr/(Zr+Ti) ratio from 0.20 to 0.40. Moreover, the lattice parameter of a- and c-axes and their ratio (c/a) of those Polar-Axis-oriented films were almost the same as the reported data for the powder, suggesting that the large strain is not remaining in those films. The relative dielectric constant (er) of the Polar-Axis-oriented Pb(Zr...
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Thick Epitaxial Pb(Zr0.35,Ti0.65)O3 Films Grown on (100)CaF2 Substrates with Polar-Axis-Orientation
Applied Physics Express, 2008Co-Authors: Takashi Fujisawa, Hiroshi Nakaki, Rikyu Ikariyama, Hitoshi Morioka, Tomoaki Yamada, Keisuke Saito, Hiroshi FunakuboAbstract:(100)/(001)-oriented tetragonal Pb(Zr,Ti)O3 (PZT) films, which were thicker than 2 µm, were epitaxially grown on SrRuO3-covered (100)Si, (100)KTaO3, (100)SrTiO3, and (100)CaF2 substrates by metal organic chemical vapor deposition. The volume fraction of the (001)-orientation almost linearly increased as the thermal strain increased during the cooling process from the deposition temperature to the Curie temperature. Consequently, perfectly (001)-oriented, i.e., Polar-Axis-oriented, thick films were obtained on CaF2 substrates with a remanent Polarization of 71 µC/cm2. This approach to grow Polar-Axis-oriented PZT thick films enabled the intrinsic piezoelectricity of PZT itself to be clarified, and has potential in novel applications.