Abstract Highly c-axis-textured Nd(Fe,Ti) 12N x films were prepared by DC magnetron sputtering on Si(1 0 0) at 450°C and subsequent nitriding. The as-deposited films contained mainly ThMn 12 structure and a second phase α-Fe. The films retained the same structure after nitriding at 450°C for 10 min, while the unit cell volume was increased by 3%. Typical coercivity and grain size of films, before and after nitiriding, were found to be `500 Oe, 140 nm'; and `2800 Oe, 170 nm', respectively. The coercivity mechanism was found to be nucleation of reverse-domain-type by fitting the Kronmüller model.