Negative magnetization in inverse Heusler alloy Cr2CoAl

Inverse Heusler alloy Cr2CoAl has been prepared by arc melting. XRD and Reitveld refinement study indicates XA lattice with B2 disorder. Magnetization measurement indicates that this alloy is ferrimagnetic below Tc=28K with soft magnetic behavior as observed from M-H curve at 4K. We observe a deviation from Curie-Weiss nature above Tc. We also observe negative magnetization in certain temperature range only when magnetization is measured at very low magnetic fields and in zero field cooled (ZFC) condition. The observed negative magnetization is not caused by the negative magnetic field trap in the magnetometer solenoid as suggested by others earlier but it appears as if the system have two competing magnetic component having positive and negative magnetization contribution. This issue is addressed in this report.