U(As1-xSex) solid solutions. II. New magnetic phase for 0.18 < x < 0.22 - art. no. 134402

We further characterize the extra diffraction peaks reported for 0.18<x<0.2 2 in the U(As1-xSex) solid solutions in the previous paper. A model based o n the spin slip hypothesis is developed that suggests that a small volume ( similar to 1%) of the crystal can be characterized in the spin-addition sta te, i.e., the regular k = 1/2 (++--) repeat is interrupted by compensating + and - "faults" that are inserted into the magnetic structure. The spacing between these faults is between 20 and 40 unit cells, depending on the tem perature and composition, x. We suggest that these spin-addition volumes fo rm the interfacial region between the high-temperature 3k and the low-tempe rature, 2k magnetic structures, both with k = 1/2.