Role of the residual amorphous phase in the intergranular magnetic coupling in nanocrystalline magnetic alloys

The temperature dependence of the coercivity (H_c) in nanocrystalline Fe₉₁Zr₇B₂ samples with various fractions of the residual amorphous phase (V_am) has been investigated with particular attention paid to the role of the residual amorphous phase in determining the intergranular magnetic coupling. H_c. in the temperature range above the Curie temperature of the residual amorphous phase (T^am _C) decreases significantly with decreasing V_am. On the contrary, H_c in the temperature range «T^am _c increases slightly with decreasing V_am. These result suggest that the intergranular magnetic coupling is dominated by the intergranular distance in the temperature range > T^am _C whereas it is independent of the intergranular distance well below T^am _C.