A grain size control technology will be described. YBa 2 Cu 3 O 7-δ thin films are grown by a pulsed laser deposition method in 400 mTorr oxygen atmosphere. The films are grown by a self-template method with various self-template growth temperatures. However the temperature of the main YBa 2 Cu 3 O 7-δ layer was fixed. Grain size of YBa 2 Cu 3 O 7-δ thin films on MgO substrates are observed by atomic force microscope. Mean diameter of grains are calculated by the number of grains in scanned area of 1 × 1 μm 2 . The mean diameters are 2.49 × 10 2 , 2.89 × 10 2 , 4.047 × 10 2 and 4.192 × 10 2 nm for films with an initial layer growth temperature of 670, 690, 714 and 730 °C, respectively. Grain size is found to depend on the initial growth stage of the YBa 2 Cu 3 O 7-δ thin film growth. These grain sizes have a strong relationship with the inverse of substrate temperature indicating thermally excited migration of YBa 2 Cu 3 O 7-δ nuclei. It is also clarified that migration length of YBa 2 Cu 3 O 7-δ nucleus is longer on an YBa 2 Cu 3 O 7-δ films than on MgO substrates.
All Science Journal Classification (ASJC) codes
- Electronic, Optical and Magnetic Materials
- Condensed Matter Physics
- Energy Engineering and Power Technology
- Electrical and Electronic Engineering