Effect of High Magnetic Field during Melt-Solidification Process on Crystal Alignment of REBCO Bulk

Abstract

ABSTRACTDisk-shaped samples of REBa2Cu3Oy ( RE123, RE = Y, Ho ) with 40%-by-molar RE2BaCuO5 (RE211, same RE of RE123 ) were melt-solidified without seeding under various magnetic fields (μ0Ha = 0 ˜ 8 T) and at various cooling rates ( Cr = 5.0, 10.0°C/h) in ambient atmosphere. Crystal alignment was evaluated by the X-ray diffraction, magnetization measurement using a SQUID magnetometer and observation of microstructure using a scanning electron microscope and a polarizing microscope. The melt grown RE123 crystals were c-axis-aligned under magnetic fields parallel to the applied field, (Ha), while the effect of alignment were systematically changed by the conditions of cooling rate and RE elements and the magnitude of Ha. The best c-axis-aligned sample showed that the value of anisotropy ( where the ratio of ΔMH//Ha /ΔMH⊥Ha) was approximately 20 at 85K and at μ0H = 0.3 T for the condition of RE = Y, Cr = 5.0°C/h, μ0Ha = 8 T.