**3.2 Comparative electron microscopic (TEM) investigation of Ce75Al25 − xGax alloys**

The TEM image of Ce75Al25 depicts homogenous contrast, and its corresponding selected area diffraction (SAD) shows single diffuse halo ring (c.f. **Figure 3(a)**). After Ga substitution, the presence of two different amorphous phases having two different contrasts can be seen in **Figure 3(b–f )**. There is one type of amorphous phase which is dispersed in the matrix of other amorphous phase. **Figure 3(b–f )** displays SAD patterns with two diffuse halos after Ga substitution. The analysis of domain size dispersed in the amorphous matrix has been carried out, and the domain size variation with Ga addition has been done using *IMAGE J* software. The value domain size (in nanometer) increases linearly with Ga addition and then obtains a saturation value, i.e., ~7 nm at x = 4 and beyond. In **Figure 3(b–f )**, insets

#### **Figure 3.**

*Bright-field TEM microstructures and the corresponding selected area diffraction patterns (shown in inset) of Ce75Al25 − xGax alloys with (a) x = 0, (b) x = 0.1, (c) x = 0.5, (d) x = 1, (e) x = 2, and (f) x = 4 (reprinted with kind permission from Reference [25], copyright 2016, Elsevier).*

also show two diffuse halos from the matrix of one amorphous phase and dispersed (secondary) amorphous phase. The clear variation in the microstructure (**Figure 3**) due to Ga addition can be seen. However, in the XRD patterns, not much variation in the intensities of two humps is found. It can be said that the two humps are due to the presence of two types of "short range order" in coexisting amorphous phases.
