The ultrathin SmCo5 nanoflakes with average thickness smaller than 50 nm are prepared by a novel method of solid particle (NaCl) and surfactant co-assisted ball milling. The as-prepared nanoflakes exhibit a narrower thickness distribution of 10-50 nm and high coercivity of 23 kOe. The possible formation mechanism of nanoflakes are proposed. Temperature dependence of demagnetization curves indic...