Polycrystalline Sm-Co-Cu films with SmCo5 phase and (0 0 0 1) texture using a dc magnetron sputtering process were successfully fabricated directly on an (0 0 0 2) Ru(Cr) underlayer on heated glass substrates at 350 °C. The mean grain size of the Sm(CoCu)5 layer is 17 nm, the smallest ever reported on SmCo5 film with perpendicular anisotropy. Strong exchange coupling between grains, as indicated by the coercivity squareness, was found in the obtained Sm(Co,Cu)5 films. An estimated perpendicular magnetic anisotropy constant, as high as 1.4 × 10 8 erg cm-3, was achieved on these films. An 'unusually' high perpendicular coercivity (11 kOe) was found on these exchange-coupled polycrystalline Sm(Co,Cu)5 films. This was explained by a pinning-site model which was supported by the measurement of the coercivity angular dependence.