REBa2Cu3Oy (REBCO, RE = rare earth) coated conductors are required for high current carrying capability. Self-organization of Ba-M-O (BMO, M = Zr, Sn, Hf...) is available to improve critical current density (Jc) in magnetic field, and suppression of a-axis grain growth contributes to enhance Jc. The former and latter are affected by the surface diffusion of adatoms and supersaturation in the REBCO film growth, respectively. We focused on surface morphologies of SmBa2Cu3Oy (SmBCO) films deposited by the pulsed laser deposition method in this paper, and estimated surface diffusion constant and supersaturation from the surface morphologies. As a result, an activation energy of the surface diffusion was approximately 2.2 eV and the value is somewhat smaller than 2.5 eV for YBCO films. Additionally, we found that a-axis grains appeared when supersaturation (Δμ) became higher than a threshold Δμ. Interestingly, a seed layer consisting of c-axis oriented SmBCO suppressed a -axis grain growth. These findings are useful to improve Jc in REBCO coated conductors.
All Science Journal Classification (ASJC) codes
- Electronic, Optical and Magnetic Materials
- Condensed Matter Physics
- Electrical and Electronic Engineering