Structural and low-temperature magnetic properties of as-quenched and annealed Ni–Si–B alloys produced by rapid solidification

Structural characterization (differential scanning calorimetry, DSC, and X-ray diffraction, XRD) and temperature dependence of the magnetization are reported in Ni80Si10B10 and Ni75Si15B10 alloy ribbons produced by rapid solidification. XDR and DSC measurements lead to confirm the amorphous character of Ni75Si15B10 alloy while the Ni80Si10B10 alloy presents a mixture of amorphous and crystalline (Nickel face-centered cubic) phase. Low-temperature magnetization dependencies were analyzed in terms of spin-wave excitation and fluctuations of the exchange interaction. While both mechanisms are relevant for the high Ni-content alloy, fluctuations of exchange could be ascribed as mechanism for low Ni-content alloy. The effect of annealing (523 and 623 K during 1 h) on the magnetic behavior is also presented. Thus, annealing of Ni75 sample at 623 K also results in appearance of highly magnetic Ni phase.