Formation of nano-amorphous domains in Ce75Al25 − xGax alloys with delocalization of cerium 4f electrons

•We report phase separation by addition of Ga at 0.01 at% in Ce75Al25 alloys.•We examine the delocalization of 4f electrons in Ce by Ce L3-edge XAS spectra.•We examine microstructural evolution of phase separation by Cahn–Hillard equation.•We compare microstructures by varying ratios of volume fractions with TEM.

The formation of nano-amorphous domains in melt spun ribbons of Ce75Al25 − xGax alloys with x = 0, 0.01, 0.1, 0.5 and 1 is reported. For x = 0, a homogenous metallic glass feature is observed. Ga substitution has led to phase separation giving rise to nano-amorphous domains in a glassy matrix. The rationale of phase separation could not be explained in terms of enthalpy of mixing of the three possible binaries in this system. The Ce L3-edge XAS spectra of melt-spun ribbons for x = 0, 0.5 and 4 have shown appearance of 4f0 delocalized states in Ga substituted alloy. Such a substitution has led to shortening of Ce–Ce distance in the alloys owing to chemical pressure. This work, therefore, opens up new direction of research for delineating issues pertaining to phase separation in amorphous systems.