(color online) Coercivity (a), remanence (b), and (BH)_max (c) dependences of stack number N in multilayer films of 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 (3nm)/Ta (20 nm). The expected μM_s and theoretical (BH)_max based on the expected μM_s are compared. The errors in the remanence and (BH)_max are shown based on the errors on the thickness of the thin films.^[22]