Exploring the details of the martensitic phase transition and magnetocaloric effect of CoMnGe0.95Ga0.05 by synchrotron and magnetic measurements

► CoMnGe0.95Ga0.05 alloy shows a structural phase transformation from hexagonal to orthorhombic. ► In CoMnGe0.95Ga0.05, the giant magnetocaloric effect is observed around room temperature. ► The maximum magnetic entropy change is −5.2 J kg−1 K−1 in magnetic field change of 1 T.