Thermal hysteresis and anisotropy in the magnetoresistance of antiferromagnetic Nd2-xCexCuO4

The out-of-plane resistivity (rho(c)) and magnetoresistivity (MR) are studied in antiferromangetic (AF) Nd2-xCexCuO4 single crystals, which have three types of noncollinear antiferromangetic spin structures. The apparent signatures are observed in rho(c)(T) measured at the zero-field and 14 T at the spin structure transitions, giving a definite evidence for the itinerant electrons directly coupled to the localized spins. One of the striking features is an anisotropy of the MR with a fourfold symmetry upon rotating the external field (B) within ab plane in the different phases, while twofold symmetry at spin reorientation transition temperatures. The intriguing thermal hysteresis in rho(c)(T,B) and magnetic hysteresis in MR are observed at spin reorientation transition temperatures.