Coexisting cubic and tetragonal phases with ferrimagnetism in equiatomic quaternary Heusler alloys: CuTCrAl (T = Co and Fe)

•Coexistence of cubic and tetragonal phases in quaternary Heusler alloys, CuCoCrAl and CuFeCrAl, revealed by XRD and neutron diffraction data.•Different magnetic states of the cubic and tetragonal phases, leading to an overall ferrimagnetic behaviour in both the alloys.•Observation of metallic character with weak localization. We have investigated two equiatomic quaternary Heusler alloys CuTCrAl (T = Co and Fe) theoretically and experimentally. Both the alloys have been characterized using X-ray Diffraction (XRD) and neutron powder diffraction (NPD). Refined results of XRD and NPD show the presence of A2/B2 type disorder with the coexistence of mixed-phase of cubic and tetragonal symmetries in CuFeCrAl and CuCoCrAl. NPD magnetic structure refinement indicates the presence of ferrimagnetism with a very low moment at low temperatures. DC magnetization results reveal the presence of weak itinerant ferromagnetic behaviour. Temperature dependence resistivity reflects the metallic character with the presence of weak localization at low temperatures. The coexistence of cubic/tetragonal and ferrimagnetism along with metallic nature in a single system is quite rare, revealing the potential of these alloys for multifarious applications.