(color online) (BH)_max as a function of the thickness of the Ta spacer layer in Ti (20 nm)/NdFeB (100 nm)Nd (10 nm)/Ta (x nm)/Fe (10 nm)/Ti (20 nm) films (x = 0–50) and the thickness of Fe layer in Ti (20 nm)/NdFeB (100 nm)Nd (10 nm)/Ta (2 nm)/Fe (y nm)/Ti (20 nm) films (y = 0–20). The dashed line stands for the (BH)_max benchmark of SLTi (20 nm)/NdFeB (100 nm)Nd (10 nm)/Ti (20 nm) thin film.^[25]