Microstructure and soft magnetic properties of ncjjiocrystalline (Co _0.77Si _0.135B _0.095) ₉₀Fe ₇Nb ₃ alloy

Microstructure and magnetic hysteretic properties of (Co _0.77Si _0.135B _0.095) ₉₀Fe ₇Nb ₃ amorphous ribbons submitted to current annealing (current density of 56 A/mm ² during 2 minutes), to develop the nanocrystallization state, are reported. Temperature dependencies of the saturation magnetization, remanence and coercivity are explained by considering the presence of two crystalline phases, namely: nanocrystals of bcc-Fe,Co(Si) and fcc-Co grains and the remaining amorphous matrix. A significant magnetic hardening is observed above the Curie point of the residual amorphous matrix, which could be ascribed to an exchange and a dipolar decoupling of the nanograins.