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We report muon spin relaxation measurements results on UCu1.5Sn2, which crystallizes in the CaBe2Ge2-type structure. Our analysis is consistent with collinear antiferromagnetic order that occurs below 108 K, in agreement with previous reports. The Brillouin-like behavior of the temperature dependence of the magnetic response is consistent with localized 5f moments. The phase transition at TN is unusual. Critical slowing down for the paramagnetic U spin fluctuations is absent, a behavior usually observed in first-order transitions. In contrast, the temperature dependence of the local field generated by the U spins is a typical second-order feature. [ABSTRACT FROM AUTHOR]

The magnetic and superconducting behaviors of sintered Sr[sub 2]YRu[sub 1-υ]Cu[sub υ]O[sub 6] (for υ = 0.05, 0.10, 0.15) were probed using transverse- and zero-field muon spin rotation (μ[sup +] SR). In general, positive muons are attracted to oxygen ions in the high-T[sub c] oxides, and so, Sr[sub 2]YRu[sub 1-υ]Cu[sub υ]O[sub 6] should (and does) present two types of μ[sup +] sites, those associated with the oxygen in the YRuO[sub 4] layers and those associated with the SrO-layer oxygen. The tranverse- and zero-field data for all three stoichiometries υ exhibit a sudden onset of magnetic structure at T[sub N] ∼ 30 K, with a static local field of ∼ 3 kG. This transition is marked by a dramatic increase in the relaxation rate as the temperature decreases below T[sub N], corresponding to an increased static disordering of the magnetic moments. Above T[sub N] no static fields are observed. Instead the data exhibit a slow dynamic depolarization, presumably due to the rapid fluctuation of paramagnetic moments. Both transverse- and zero-field data also indicate a smaller second component (∼ 10%) which we associate with the SrO layer, exhibiting superconducting behavior in transverse field with an observed T[sub c] ≈ T[sub N] ∼ 30 K. [ABSTRACT FROM AUTHOR]

We report muon spin relaxation measurements results on UCu1.5Sn2, which crystallizes in the CaBe2Ge2-type structure. Our analysis is consistent with collinear antiferromagnetic order that occurs below 108 K, in agreement with previous reports. The Brillouin-like behavior of the temperature dependence of the magnetic response is consistent with localized 5f moments. The phase transition at TN is unusual. Critical slowing down for the paramagnetic U spin fluctuations is absent, a behavior usually observed in first-order transitions. In contrast, the temperature dependence of the local field generated by the U spins is a typical second-order feature. [ABSTRACT FROM AUTHOR]