Figure 3. MFM image series for the TR process near TC′.
(a–n) The images taken along the ZFW curve after cooled at 2.0 T from room temperature. A small field of 300 Oe is applied perpendicular to the film plane to enhance the magnetic signal. The scale bar is 2 μm and the scanned areas are 8 μm × 8 μm for all images. The images with the same frame colour are scanned successively at a fixed temperature but at different time as denoted. For example, c and d are taken 3 and 8 h later than b, respectively. The dark arrows in e,g, and m indicate sharp discontinuities. The colour scales for a–n are 1.0, 1.5, 1.5, 1.5, 2.0, 2.0, 2.5, 2.5, 2.0, 2.0, 1.5, 1.5, 1.5 and 1.0 Hz, respectively. Unlike the images taken during field sweep (under much higher fields), where only bright areas are observed for the COI domains, now the left and right edges of a certain COI domain are bright and dark, respectively, leading to a three-dimensional appearance.