force and the driving force that tends to minimize the total
surface energy of the system. The grains could not be seen
clearly, and this may be because of masking caused by the
gold coating on the film’s surface. The thicknesses of the films
were decreased as the annealing increased and ranged from
408 nm to 249 nm. We can conclude that for different annealing temperatures, the crystallite sizes of Er0.4Y2.6Fe5O12 films
are increased, while the films thicknesses were reduced. This
is probably due to the different ionic radius of Er3+ (1.03 >)
which is less than Y3+ (1.04 >), which leads to some apparent
variation about the crystalline lattice.