Atomic-resolution HAADF-STEM images of the Z-phase. a Experimental (left), b atomic models (center) and simulated (right) atomic resolution STEM-HAADF Z-contrast images for c SmCo3 and d Zr2SmCo9. All images are viewed along the  zone axis. The experimental image was filtered by principal component analysis to reduce the effect of noise. Scale bar, 5 Å