The coercive behavior and the energy product for multilayers of FeCo and Sm-Fe-N

► We studied demagnetization behavior of multilayer composite Sm2Fe17N3/FeCo. ► The composite demonstrates the increase of energy product with adding of soft phase. ► There is significant increase of thermal fluctuation of soft phase spins with temperature. ► Strong thermal fluctuations lead to substantial reduction of the remanence.