Magnetic-hyperfine-field distributions in amorphousFe90Zr10Invar alloy and the effect of replacing Fe with Ni and/or Co

Hyperfine-field distributions P(H) were evaluated from Mössbauer spectra of amorphous (a-) ${\mathrm{Fe}}_{90}$ ${\mathrm{Zr}}_{10}$, (${\mathrm{Fe}}_{0.8}$ ${\mathrm{Co}}_{0.2}$ ${)}_{90}$ ${\mathrm{Zr}}_{10}$, and (${\mathrm{Fe}}_{0.8}$ ${\mathrm{Co}}_{0.1}$ ${\mathrm{Ni}}_{0.1}$ ${)}_{90}$ ${\mathrm{Zr}}_{10}$ alloys recorded at 85 and 300 K with the use of a model-independent field-distribution analysis. Our data analysis unambiguously shows that P(H) for a-${\mathrm{Fe}}_{90}$ ${\mathrm{Zr}}_{10}$ at 85 K consists of two broad Gaussian distributions centered around ∼96 and ∼200 kG with standard deviations of 36 and 46 kG, respectively. Partial replacement of Fe with (Co,Ni) results in a complete suppression of the low-field peak, and P(H) at 85 K now exhibits only one Gaussian peak at 312 and 296 kG, respectively, for Co- and (Co,Ni)-substituted alloys. Together with other relevant results on a-${\mathrm{Fe}}_{100\mathrm{-}\mathrm{x}}$ ${\mathrm{Zr}}_{\mathrm{x}}$ alloys existing in the literature, our data find a straightforward explanation in terms of a model recently proposed by one of us.