Giant effect of Sm atoms on time stability of (NdDy)(FeCo)B magnet
Small amount of Sm additives (∼ 1 -3 at.%) slow down two times relaxation of magnetization of (NdDy)(FeCo)B alloys. Effective freezing of spontaneous relaxation of magnetization is caused by the enhancement of potential barriers of the domain walls. Easy plane single-ion anisotropy of Sm strongly disturbs the potential relief of the domain walls. The experimental results can be used to stabilize hard magnets.