Giant spontaneous resistivity jumps in La0.825Ce0.175Fe12B6

Abstract

We report the observation of spontaneous and very sharp resistivity jumps at low temperatures in the antiferromagnetic itinerant-electron system La0.825Ce0.175Fe12B6. This intermetallic compound undergoes multiple magnetic transformations, antiferromagnetic-ferromagnetic (AFM-FM) and ferromagnetic-paramagnetic (FM-PM), triggered by changes in both the temperature and the applied magnetic field. The magnetoresistance isotherms display irreversible abrupt steps at T ≤ 4 K, whereas the field dependence of the resistivity becomes smooth above 4 K. Meanwhile, the evolution with time of the electrical resistivity exhibits a huge spontaneous jump after an incubation time when both the applied magnetic field and temperature are constant. A giant negative magnetoresistance (MR = −71%) is discovered associated with the magnetic-field-induced first-order AFM-FM transition.