MAGNETIC-PROPERTIES OF UN STUDIED BY MU-SR

In the paramagnetic range (T > T(N) = 5 3 K) fluctuations of the momen ts on uranium are too fast to produce a sizeable damping of the muSR s ignal even close to T(N). This rules out the formation of a magnetic p recursor state as seen in UAs. In the antiferromagnetic regime all con tributions to the field at the muon site cancel due to symmetry. Compa rison with analogous data on other uranium mono-pnictides show that th e magnitude of the field distribution width in the type I-single k ant iferromagnetic state is not an intrinsic property of these materials.