MAGNETIC EVOLUTION OF THE AMORPHOUS AND NANOCRYSTALLINE PHASES AND INTERPHASE COUPLING DURING THE CRYSTALLIZATION OF FE87ZR6B6CU - A FERROMAGNETIC-RESONANCE STUDY

We present results of ferromagnetic resonance measurements on the allo y Fe87Zr6B6Cu. These show the changes occurring in the sample, both ma gnetically and structurally, during the crystallization process. In th is alloy the amorphous phase gradually crystallizes, forming nanocryst allites of alpha-Fe in a remaining ferromagnetic amorphous matrix. Res ults show evidence of a disordered and Fe-rich interphase region surro unding the Fe crystallites. This interphase region initially grows alo ng with the growth of the Fe nanocrystals. However, in the latter stag es of the Fe nanocrystallization, this phase also crystallizes into th e Fe phase and other crystalline phases, and disappears at the end of the Fe crystallization and the beginning of second crystallization. Ev idence of an interface localized spin wave mode at the boundary betwee n the amorphous ferromagnetic and Fe phases in the early stages of cry stallization is also observed. At higher annealing temperatures, we ob serve another resonance absorption feature. This is due to the onset o f the second stage of crystallization, where FeZr and iron-boride phas es form. The results of the ferromagnetic resonance are analyzed in a multiphase regime, where the importance of the magnetic coupling betwe en the various magnetic phases is evident. A minimum of the in-plane a nisotropy is found to coincide with the softest magnetic properties of this alloy. [S0163-1829(98)03441-9].