Presentation Information
[WBP1-16]Correlation Between Plume Color Metrics and Superconducting Properties in YBCO Thin Films Prepared by Pulsed Laser Deposition
*Ryotaro Matsuda1, Iori Kadota1, Yuto Tanaka1, Noriyuki Taoka1, Yoshiyuki Seike1, Tatsuo Mori1, Yusuke Ichino1,5, Keiichi Horio2,5, Ataru Ichinose3,5, Tomoya Horide4,5, Kaname Matsumoto4,5, Yutaka Yoshida4,5 (1. Aichi Inst. of Technol. (Japan), 2. Kyushu Inst. of Technol. (Japan), 3. Cent. Res. Inst. of Elect. Power Ind. (Japan), 4. Nagoya Univ. (Japan), 5. JST-CREST (Japan))
Keywords:
Plume,Pulsed Laser Deposition,YBa2Cu3Oy
Pulsed Laser Deposition (PLD) is a useful technique for creating thin films of YBa2Cu3Oy (YBCO). The PLD process involves the creation of a columnar ablation plasma emission, known as a plume, which is observed between the target and the substrate. The plume's shape is affected by non-quantitative factors like fluctuations in laser energy, oxygen pressure, and the condition of the target. These factors make it difficult to maintain a consistent deposition environment, which can lead to poor reproducibility of superconducting properties, such as the critical temperature (Tc). This study was conducted to address this challenge by examining the correlation between changes in the plume's visual information (RGB, HSV) and changes in thin-film properties such as compositional ratio and Tc.
YBCO thin films were deposited on SrTiO3(100) single-crystal substrates using the PLD method. A depth camera (Intel Realsense Depth Camera D405) was used to photograph the plume during deposition. The captured images were converted to grayscale, binarized, and a circumscribed rectangle was drawn. The average RGB and HSV values were calculated within this rectangle. The substrate temperature was set at 920 ℃ and a Nd:YAG laser (266 nm wavelength, 10 Hz repetition rate) was used. Laser energy was varied from 10 to 20 mJ, and oxygen pressure from 0.1 to 70 Pa. Tc was defined as the zero-resistance temperature, where the electrical resistivity dropped below 1 μΩcm, as measured by the four-probe method. The compositional ratio of the thin film was measured using SEM-EDX.
Plume images showed that at 0.1 Pa oxygen pressure, the plume was a white emission near the target. At 5 Pa, it emitted a red light extending from the target to the substrate, and at 30 Pa, this region became a color closer to white. The compositional ratio of Cu to Y in the thin film (Cu/3Y) tended to increase with increasing oxygen pressure, with a high correlation coefficient of 0.83. This suggests that a change in oxygen pressure affects both the plume's visual information and the composition of Cu in the thin film. It is believed that the change in the composition of Cu within the plume influenced the plume's color, as the emission spectra for Cu and CuO are in the visible light range. A contour plot of Tc was created against the feature value BS (B component of RGB multiplied by the S component of HSV) and the V component of HSV. The Tc had a negative correlation with both B S and V, and conditions were found for these values that resulted in a high Tc. This result indicates that Tc can be predicted from the plume's color information, which suggests the potential for in-situ monitoring and control of superconducting properties. Future work will focus on investigating the physical meaning of the visual information and its correlation with various thin-film properties.
YBCO thin films were deposited on SrTiO3(100) single-crystal substrates using the PLD method. A depth camera (Intel Realsense Depth Camera D405) was used to photograph the plume during deposition. The captured images were converted to grayscale, binarized, and a circumscribed rectangle was drawn. The average RGB and HSV values were calculated within this rectangle. The substrate temperature was set at 920 ℃ and a Nd:YAG laser (266 nm wavelength, 10 Hz repetition rate) was used. Laser energy was varied from 10 to 20 mJ, and oxygen pressure from 0.1 to 70 Pa. Tc was defined as the zero-resistance temperature, where the electrical resistivity dropped below 1 μΩcm, as measured by the four-probe method. The compositional ratio of the thin film was measured using SEM-EDX.
Plume images showed that at 0.1 Pa oxygen pressure, the plume was a white emission near the target. At 5 Pa, it emitted a red light extending from the target to the substrate, and at 30 Pa, this region became a color closer to white. The compositional ratio of Cu to Y in the thin film (Cu/3Y) tended to increase with increasing oxygen pressure, with a high correlation coefficient of 0.83. This suggests that a change in oxygen pressure affects both the plume's visual information and the composition of Cu in the thin film. It is believed that the change in the composition of Cu within the plume influenced the plume's color, as the emission spectra for Cu and CuO are in the visible light range. A contour plot of Tc was created against the feature value BS (B component of RGB multiplied by the S component of HSV) and the V component of HSV. The Tc had a negative correlation with both B S and V, and conditions were found for these values that resulted in a high Tc. This result indicates that Tc can be predicted from the plume's color information, which suggests the potential for in-situ monitoring and control of superconducting properties. Future work will focus on investigating the physical meaning of the visual information and its correlation with various thin-film properties.