Giant-magnetoresistance anomaly associated with a magnetization process in UFe4Al8

Magnetoresistance and magnetization measurements on a U${\mathrm{Fe}}_4$ ${\mathrm{Al}}_8$ single crystal are reported. A strong anisotropic magnetoresistance is found in this compound and is used to prove the ferromagnetic order of the U lattice. A strong anomaly in the parallel and perpendicular magnetoresistance is interpreted as an unusual magnetization process in which the magnetization remains blocked perpendicularly to the applied magnetic field. This interpretation is confirmed by the magnetization measurements.