Metastable alloys of nominal composition (Fe_0.5Cu_0.5)_100-xZr_x (x=0-17 at.%) have been synthesized by high energy ball milling. In spite of the high and positive enthalpy of mixing between Fe and Cu, nanocrystalline or amorphous alloys have been obtained depending on the Zr content. Alloys exhibit a ferromagnetic behavior with a Curie temperature below room temperature. The thermal dependence of the thermorremanence shows a anomalous increase above the Curie temperature. This behavior seems to be related with a magnetovolume effect. Extended X-ray absorption fine structure (EXAFS) measurements have been performed to explain this effect. Preliminary results seem to indicate an almost negligible thermal expansion at temperatures below Tc, while normal thermal expansion takes place at higher temperatures.