Cross-sectional TEM images of multilayer films Ta (50 nm)[Nd–Fe–B (30 nm)/Nd (3 nm)/Ta (1 nm)/Fe₆₇Co₃₃(10 nm)/Ta (1 nm)]_N/Nd–Fe–B (30 nm)/Nd (3 nm)/Ta (20 nm) with stack numbers (a), (b) N = 4, (c)–(e) N = 9, and (f) N = 14.^[22]