Effect of Tb substitution on the magnetic properties of exchange-biased Nd2Fe14B/Fe3B

Tb-substituted (Nd,Tb)2Fe14B/Fe3B nanocomposite ribbons have been synthesized by melt spinning of Nd3Tb1Fe76Cu0.5Nb1B18.5 alloys. Tb substitution has significantly enhanced the value of coercivity and Curie temperature. Highest value of coercivity has been obtained as 4.76 kOe for the sample annealed at 953 K for 10 min. Curie temperature of Tb substituted sample, Nd3Tb1Fe76- Cu0.5Nb1B18.5 is 549 K while Curie temperature of the sample without Tb, Nd4Fe76Cu0.5Nb1B18.5 is 535 K. Recoil hysteresis loops measured along the major demagnetization curve are steep having small recoil loop area. Temperature dependence of coercivity, remanent ratio and maximum energy product have been measured for the sample annealed at 893 K and 923 K for 10 min. At 5 K, coercivity and maximum energy product of the sample annealed at 893 K for 10 min are 5.2 kOe and 11.5 MGOe respectively and the sample annealed at 923 K for 10 min are 6 kOe and 13.1 MGOe respectively.