MAGNETIC-PROPERTIES OF ERRU2SI2, EROS2SI2 AND DYRU2SI2

ErRu2Si2, ErOs2Si2 and DyRu2Si2 have been investigated by magnetizatio n, neutron diffraction and Mossbauer measurements. These intermetallic s were shown to order magnetically at low temperature and to exhibit m etamagnetic-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 b oth compounds the moments are aligned along the b-axis and a partial s quaring of the modulation was inferred from Mossbauer and neutron diff raction 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 paralle l to the c-axis. A squaring up of the magnetic structure occurs at abo ut 19 K; it is complete at 1.6 K where mu(Dy) = 10mu(B), in agreement with the Mossbauer data.