(a) curves measured from the 10, 20, and 30 nm films at 0 T, and the 60 nm film at 0, 1, and 3 T. The films were annealed at for 3 or 5 h, as denoted. The arrows show the data recorded during the cooling or warming processes. (b) XRD linear scans on (002) reflections from the 20, 30, and 60 nm films, noting that the latter was annealed at for 30 h. [(c) and (d)] AFM images from the 20 and 30 nm films. The insets show the images under a higher magnification, where the 20 nm film with a more enhanced AFI phase fraction shows domains of larger atomically flat area, as was confirmed by the height scans (not shown).
curves measured from the 10 and 20 nm films during FC-FW [(a) and (b)] and ZFC-FW [(c) and (d)] under the various magnetic fields as denoted. The inset in (d) shows curves at 10 K measured from the same films.
curves measured during FW at 0.75 T (symbols) after cooling the (a) 10 and (b) 20 nm films at 0, 0.75, and 6 T to 5 K. The curves during the cooling were shown with the lines. (c) curves during FW at 0 and 0.5 T after cooling the 30 nm film at 4 T. The curves during FC-FW at 0 and 0.5 T were also shown for comparison. (d) curves during FW at 0.25 T, which were recorded after cooling the 30 nm film under 4 T to a different target temperature within 10–200 K, as denoted.
(a) curves measured after ZFC the 30 nm film from 320 K to the different target temperatures. The arrows indicate the direction of the field cycling. The inset illustrates the phase diagram with the and derived from the and curves, respectively. Note that even at zero-field the AFI dominated state is still coexisted with the FM phase, thus the reentrant AFI phase upon reducing , as reflected by the curves, is not included in the phase diagram. (b) curves during FC-FW at 0.05 T from the 60 nm film annealed for 30 h. The bottom inset shows the curves after subtracting the contribution from the substrate, while the top one shows correspondingly the curves at zero-field. The curve from the 60 nm film annealed for 5 h was also inserted for comparison. Note that the sharp increase in the below 25 K may arise from the strong anisotropic paramagnetic background from the substrate especially at the lower temperatures, which is hard to be subtracted.
Successive curves (line, labeled as 1, 2, and 3) measured after ZFC the samples (10, 20, and 30 nm) from 320 K to (a) 5 K, (b) 100 K, and (c) 170 K. Those from the single field cycling (line and symbol) after the same thermal process were also shown for comparison.
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