MO装置開発 Core part of RTR-MOI Photograph of core part
MOIに用いる磁気光学膜の作製 MO装置開発 The indicator films are necessary to observe MO images. R1 R2 R3 R4 R5 R6 #1 20 6.5 10 0.13 - 2.5 #2 20 6.4 10 0.14 - 2.5 #3 20 6.7 10 0.12 - 2.5 #4 20 6.9 10 0.11 - 2.5 A lot of defects ! We obtain high quality MO indicator films ! Low defect density !
初期のIBAD/PLD線材の磁束侵入の様子 素線評価 40K ZFC IBAD/PLD Fujikura #106880 10mT 20mT 30mT 40mT 50mT 60mT Defects 10mm Remanent 70mT 80mT 90mT 100mT IBAD/PLD線材への磁束侵入は左右均一 Dendriticな磁束侵入がµmオーダで折れ曲がっている バッファ層の粒界の細かさを反映している
Previous study of MOI on coated conductors in USA Flux penetration into RABiTS tape YBCO(PLD)/CeO2/YSZ/CeO2/Ni D. M. Feldmann (Polyanskii group) et al. Appl. Phys. Lett. 77 (2000)2906. 15K 600 Oe Rolling aligned Ni has a large grain (~ 100µm). Grain boundaries are connected each other with small angles, and magnetic flux penetrates along grain boundaries.
RTR-MOI装置によるMO観察結果 素線評価 [NCCC] RTR-MOI装置によるMO観察結果 Ic~250A IBAD/PLD (Total length 1.5m) ZFC 40K 80 mT 150 mm 10 mm This tape has only a few defects. Magnetic flux penetration is uniform for both width and length directions. Suitable for scribing process
Movie of the observation result by RTR-MOI 素線評価 Movie of the observation result by RTR-MOI [NCCC] Shooting time ~ 1 hour IBAD/PLD (Total length 1.5m) Ic ~250A ZFC 40K 50 mT Tape edge 10 mm (width)
Spatial resolution of RTR-MOI equipment 素線評価 Both Hall sensor array equipment (tapestar@THEVA) and our new RTR-MOI can visualize 2D-image of flux distribution. Using same sample : TFA-MOD (Ic~100A) [SRL, early stage specimen] 40K, 50mT RTR-MOI 10 mm (width) 77K, 20mT Hall sensor array (Tapestar@THEVA) There are many defects in this sample. Hall sensors array can detect same defect. 1µm - 10µm MOI has a higher spatial resolution !
Comparison with other characterization methods Spatial resolution Hall sensor array(Tapestar@THEVA) RTR MOI Field coated conductor Hall sensor array system Moving RTR I-V measurement RTR I-V meas. Measuring speed(m/h) We must choose measuring method by the purpose!