MAGNETIC-PROPERTIES OF ERRU2SI2, EROS2SI2 AND DYRU2SI2

ErRu2Si2, ErOs2Si2 and DyRu2Si2 have been investigated by magnetization, neutron diffraction and Mossbauer measurements. These intermetallics were shown to order magnetically at low temperature and to exhibit metamagnetic-like behaviour. ErRu2Si2 (T(N) = 5.7 K) and ErOs2Si2 (T(N) = 4.7 K) present sine-modulated magnetic structures characterized by a wavevector Q = (q(x), 0, 0) with q(x) = 115 (Ru) and 5/17 (0s). In both compounds the moments are aligned along the b-axis and a partial squaring of the modulation was inferred from Mossbauer and neutron diffraction measurements performed at 1.6 K. DyRu2Si2 orders at T(N) = 29 K with a sine-wave modulation, Q = (2/9, 0, 0), of the moments parallel to the c-axis. A squaring up of the magnetic structure occurs at about 19 K; it is complete at 1.6 K where mu(Dy) = 10mu(B), in agreement with the Mossbauer data.