• Journal of the Korean Ceramic Society
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• v.40 no.2
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• pp.153-158
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• 2003

Self-patterning of thin films using photosensitive sol solution has advantages such as simple manufacturing process compared to photoresist/dry etching process. In this study,$La_{0.5}SR_{0.5}CoO_3$(LSCO) thin films as an electrode material for ferroelectric memories have been prepared by spin coating method using photosensitive sol solution. La-2methoxyethoxide, Sr-ethoxide, Co-2methoxyethoxide were used as starting materials. As UV exposure time to the LSCO gel thin film increased, the UV absorption peak intensity of metal${beta}$-diketonate decreased due to reduced solubility by M(metal)-O-M bond formation. Solubility difference by UV irradiation on LSCO gel thin film allows to obtain a fine patterning of thin film. The LSCO thin films annealed over$680{\circ}C$ in air showed perovskite phase and the lowest resistivity$(4{ imes}10^{-3}{Omega}cm)$ of the thin films were obtained by annealing at$740{\circ}C$.

• Progress in Superconductivity and Cryogenics
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• v.23 no.2
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• pp.10-13
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• 2021

Superconductor-ferromagnet thin film heterostructure is an ideal system for studying the interplay between superconductivity and ferromagnetism. These two antagonistic properties combined in thin film heterostructure create interesting proximity effects such as spin-triplet superconductivity. Thin film heterostructure of optimally doped La_2-xSr_xCuO₄(LSCO) cuprate superconductor and SrRuO₃(SRO) ruthenate ferromagnet has been grown by pulsed laser deposition. Its temperature-dependent resistivity and Hall effect measurements show that our LSCO/SRO heterostructure has both superconductivity and ferromagnetism. In the Hall effect measurement results, we find additional hump-like structures appear in the anomalous Hall effect signal in the vicinity of superconducting transition. We conclude that giant magnetoresistance of the LSCO layer distorts the AHE signal, which results in a hump-like structure.

• Journal of the Korean Ceramic Society
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• v.41 no.1
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• pp.13-18
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• 2004

$La_{0.5}Sr_{0.5}CoO_3$ (LSCO) electrodes were prepared on ferroelectric $Sr_{0.9}Bi_{2.1}Ta_2O_9$(SBT) thin films by spin coating method using photosensitive sol-gel solution. Self-patterning technique of photosensitive sol-gel solution has advantages such as simple manufacturing process compared to photoresist/dry etching process. Lanthanum(III) 2-methoxyethoxide, Stronitium diethoxide. Cobalu(II)2-methoxyethoxide were used as starting materials for LSCO electrode. UV irradiation on LSCO thin films lead to decrease solubility by M-O-M bond formation and the solubility difference allows us to obtain self-patternine. There was little composition change of the LSCO thin films between before leaching and after leaching in 2-methoxyethanol. The lowest resistivity of LSCO thin films deposited on $SiO_2$/Si substrate was $1.1{\times}10^{-2}{\Omega}cm$ when the thin film was ennealed at $740^{\circ}C$. The values of Pr/Ps and 2Pr of LSCO/SBT/Pt capacitor on the applied voltage of 5V were 0.51, 8.89 ${\mu}C/cm^2$, respectively.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2010.06a
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• pp.214-214
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• 2010

The 0.65Pb($Mg_{1/3}Nb_{2/3})O_3-0.35PbTiO_3$ (PMN-PT) thin films with $La_{0.5}Sr_{0.5}CoO_{3-\delta}$ (LSCO) bottom electrodes were grown on $CeO_2$/YSZ/Si(001), Pt/$TiO_2$/Si and $SrTiO_3$ (STO) substrates using conventional pulsed laser deposition (PLD) at a substrate temperature of $550^{\circ}C$. Since generally the crystallographic orientation of the bottom electrode induces the orientation of the films deposited on it, it allows us to observe the influence of the PMN-PT film orientation on the electrical properties. Phi scan done on PMN-PT/LSCO thin films shows epitaxial behavior of the films grown on sto substrates and $CeO_2$/YSZ buffered Si(001) substrates, and (110) texture on Pt/$TiO_2$/Si substrates. Polarization-electricfield (P-E) measurement shows good hysteresis behavior of PMN-PT films with remnant polarization of 18.2, 8.8, and $4.4{\mu}C/cm^2$ on $CeO_2$/YSZ/Si, Pt/TiO2/Si and STO substrates respectively.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2003.05c
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• pp.116-119
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• 2003

Self-patterning of thin films using photosensitive sol solution has advantages such as simple manufacturing process compared to photoresist/dry etching process. In this study, ferroelectric $Sr_{0.9}Bi_{2.1}Ta_2O_9$(SBT) and $La_{0.5}Sr_{0.5}CoO_3$(LSCO)thin films have been prepared by spin coating method using photosensitive sol solution. $Sr(OC_2H5)_2$, $Bi(TMHD)_3$ and $Ta(OC_2H)_5)_5$ were used as starting materials for SBT solution and $La(OCH_2CH_2OCH_3)_3$, $Sr(OC_2H_5)_2$, $CO(OCH_2CH_2OCH_3)_2$ were used for LSCO solution. Solubility difference by UV irradiation on LSCO thin film allows to obtain a fine patterning due to M-O-M bond formation. The lowest resistivity($4{\times}10^{-3}{\Omega}cm$) of LSCO thin films was obtained by annealing at $740^{\circ}C$.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.27 no.5
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• pp.297-302
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• 2014

$La_{0.5}Sr_{0.5}CoO_3$ (LSCO) electrode thin films with a resistivity of ~ 1,600 ${\mu}{\Omega}cm$ were grown on c-$Al_2O_3$ (0001) substrate. $ZnSnO_3$ (ZTO) thin films with different thicknesses were directly grown on LSCO/c-$Al_2O_3$ (0001) substrates at a substrate temperature that ranged from 550 to $750^{\circ}C$ using Pulsed Laser Deposition (PLD). The secondary phase $Zn_2SnO_4$ occurred during the growth of ZTO films and it became more significant with further increasing substrate temperature. Polarization-electric-field (P-E) hysteresis characteristics, with a remnant polarization and coercive field of 0.05 ${\mu}C/cm^2$ and 48 kV/cm, respectively, were obtained in the ZTO film grown at $700^{\circ}C$ in 200 mTorr.

• Bulletin of the Korean Chemical Society
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• v.29 no.12
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• pp.2325-2326
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• 2008

• Journal of the Korean Ceramic Society
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• v.35 no.7
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• pp.647-647
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• 1998

(La,Sr)CoO3/Pb(Zr,Ti)O3/(La,Sr)CoO3 (LSCO) heterostructures have been grown on LaAlO3 substrates by pulsed laser deposition (PLD) to investigate asymmetric polarization of Pb(Zr,Ti)O3 (PZT) thin flims with different electrode configuration. P-V hysteresis loop of LSCO/PZT/LSCO was symmetric. However, LaCoO3 (LCO_/PZT/LSCO showed a largely asymmetric P-V hystersis loop and large relaxation of the remanent polarization at the negatively poled state, which means that the negatively poled state was unstable. On the other hand, LSCO/PZT/LCO exhibited large relaxation of the positively poled state. The asymmetric behavior of the polarized states implies the presence of an interal electric firld inside the PZT layer. It is suggested that internal electric field is caused by built-in voltages at LCO/PZT and LSCO/PZT interfaces. The built-in voltages at LCO/PZT and CSCO/PZT interfaces were 0.6 V and -0.12 V, respectively.

• Journal of the Korean Vacuum Society
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• v.8 no.4A
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• pp.425-431
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• 1999

$Pb(Zr_{0.52}, Ti_{0.48})O_3$ (PZT) thick films as an actuating material with conducting oxides, $(La_{0.5}Sr_{0.5}) CoO_3$ (LSCO), have been fabricated by sol-gel method for Optical Micro-Electro-Mechanical System (MEMS) devices, in which PZT/LSCO/SiO2 structures were used. In order to improve the adhesion to LSCO solution in order to enhance the wetting behavior of a water-based LSCO precursor solution and further to improve the adhesion between LSCO and $SiO_2$ layers. PZT films were made using 1-3 propanediol based precursor solution which has a high viscosity and a boiling point appropriate for thick film fabrication. In the precursor solution, Ti-propoxied and Zr-propoxied are partially substituted with acetylacetone to achieve the solution stability while maintaining reactivity. Crack free PZT films (0.8~1$\mu\textrm{m}$) have been successfully fabricated at crystallization temperatures above $700^{\circ}C$. Dielectric constants and dielectric losses of the PZT films were 900~1200and 2~5%, respectively. Piezoelectric constant $d_{33}$ of the PZT films constrained by a substrate were 200pm/V at 100kV/cm.

• Transactions of the Korean Society of Mechanical Engineers B
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• v.30 no.12 s.255
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• pp.1211-1217
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• 2006

This study is focused on oxidation prevention of STS430, which is generally used as solid oxide fuel cell(SOFC) interconnect at intermediate operating temperatures with oxidation-proof coatings. Inconel, $La_{0.6}Sr_{0.4}CoO_3(LSCo)$ and $La_{0.6}Sr_{0.4}CoO_3(LSCr)$ were chosen as coating materials. Using a radio frequency magnetron sputtering method, each target material was deposited as thin film on STS430 and was analyzed to find out favorable conditions. In this study, LSCr-coated STS430 can reduce electrical resistance to 1/3 level, compared with uncoated STS430. Also, long-term durability test at $700^{\circ}C$ for 1000 hours tells that LSCr thin layer performs an important role to prohibit serious degradations. Superior oxidation-resistant characteristic of LSCr-coated STS430 is attributed to the inhibition of spinel structure formation such as $MnCr_2O_4$.