Magnetic structures of orthorhombic rare earth stannides LSn2 (L = Tb–Tm)

The magnetic structures of the orthorhombic compounds LSn2 (S.G.: Cmcm; L = Tb–Tm) have been determined from neutron diffraction studies. The compounds LSn2 (L = Tb, Dy, Ho Er) order below 26.7, 17.2, 7.8 and 4.5 K, respectively, in a sine-modulated structure characterized by the propagation vector k = (≈0.39, 0, ≈0.41). Below 12.7, 5, 4.8 and 2 K, respectively, these compounds undergo a transition towards a collinear antiferromagnetic structure characterized by the propagation vector k = (0, 0, 1/2) for Tb and Er, k = (1/2, 1/2, 0) for Ho and k = (1/2, 1/2, 1/2) for Dy. The compound TmSn2 orders below 4.0 K in a sine-modulated structure characterized by the propagation vector k = (0, 0.667, 0.380). The moment direction is close to [0 0 1] for L = Tb, Dy, Ho and aligned along [1 0 0] for L = Er, Tm. The results are discussed and a relative scale of the stability of the moment configuration in the (0 1 0) plane is proposed.