Structural and magnetic properties of CoIrMnAl equiatomic quaternary Heusler alloy epitaxial films designed using first-principles calculations

•CoIrMnAl was computationally designed as one of the advanced materials for spintronics.•We obtained B2 ordered CoIrMnAl thin films with the lattice constant similar to that predicted in fully ordered alloy.•Magnetization at 10 K and Curie temperature measured were about 70% of the predicted values in fully ordered alloys.•Experimental data were well explained with ferrimagnetism due to Co-Mn swap disorders predicted from ab-initio calculation.