[en] A paramagnetic amorphous Fe_0.33Zr_0.67 alloy has been studied with Mossbauer spectroscopy and SQUID magnetometry. Low-field magnetization measurements revealed the existence of superparamagnetic nanoparticles of thousands of μ_B embedded in the alloy with a blocking temperature of 50 K. A saturation of local moments (15.9 μ_B), possibly clusters of a few Fe ions, is observed at 4.6 K around 10 kOe. The temperature dependence of the high-field magnetic susceptibility of Fe_0.33Zr_0.67 is interpreted with Curie's law for these Fe clusters and nanoparticles. (author)