Evolution of the modulated antiferromagnetic structure of CeAl2 in the presence of nonmagnetic impurities

Neutron diffraction studies show that the alloy system Ce_1-xLa_xAl₂ with x = 0.1 and 0.2 orders in the same incommensurate modulated antiferromagnetic structure as the pure compound CeAl₂. The existence and concentration dependence of a commensurate extra reflection ($\text{5}\text{2}$$\text{3}\text{2}$$\text{1}\text{2}$) is interpreted as being due to a modulation quenching of the CeAl₂ structure. This is in contrast to the suggestion that the magnetic order of CeAl₂ can be described by a triple-q structure.