Crystal growth of Bi-2201 phase in high magnetic fields

The crystal growth of Bi-2201 phase during partial-melting and solidification in high magnetic fields was reported. Thin crystals (∼20 μm) with a size of 5-10 mm² exist only in the surface layers of samples treated in zero magnetic field. Whereas thick crystals (∼100 μm) exist not only on the surface, but also in the center of samples treated in 8 T magnetic fiel. T_c of Bi-2201 phase treated in 0 T is higher than that treated in 8 T. Bi-2201 phase and Bi-2212 phase coexist in the sample treated in 0 T, whereas only Bi-2201 phase exists in the sample treated in 8 T. For the sample treated in 8 T magnetic field, a clear second peak structure was observed in the magnetic hysteresis loop in the direction H_m∥H_a at 5 K, and the width of the hysteresis loop ΔM at 5 K and 0 T in the direction H_m∥H_a is about 10 times as large as that in the direction H_m⊥H_a, indicating that for this sample an obvious anisotropy exists and the Bi-2201 grains align with their c-axes parallel to H_a.