Detailed measurements of M ͑2 K, H, ͒ of HoNi 2 B 2 C, where is the angle that the applied field H makes with the ͓110͔ axis while remaining perpendicular to the crystallographic c axis, reveal three metamagnetic transitions with angular dependences H c1 ϭ͑4.1Ϯ0.1 kG͒/cos͑͒, H c2 ϭ8.4Ϯ0.2 kG/cos͑͒, and H c3 ϭ͑6.6Ϯ0.2 kG͒/sin͑͒, where ϭϪ45 is the angle from the ͓100͔ axis. The high-field saturated moment, M sat Ϸ10 B cos is consistent with the local moments being confined to the ͓110͔ direction. The locally saturated moments for fields between H ci ͑iϭ1,2,3͒ also manifest angular dependences that are consistent with combinations of local moments along ͓110͔ axes. Analysis of these data lead us to infer that the net distribution of moments is ͑↑↓↑↓↑↓͒ for HϽH c1 , ͑↑↑↓↑↑↓͒ for H c1 ϽHϽH c2 , ͑↑↑→↑↑→͒ for H c2 ϽHϽH c3 , and ͑↑↑↑↑↑↑͒ for HϾH c3. ͓S0163-1829͑97͒02902-0͔

Ultrathin ferromagnetic films with perpendicular spin anisotropy can possess an alternating up-down stripe-domain structure, with widths L 5. Considering the two inequivalent types of stripe domains to form a single unit, this structure may be thought of as a two-dimensional smectic crystal. It is subject to a weak stripe orientation energy. With increasing temperature the domain system changes from a smectic crystal phase to an "Ising nematic" phase, and then to a "tetragonal liquid" phase. We discuss its possible phase diagrams, in (H"H~~, T) space. This sequence of phases can occur whether or not the system ultimately undergoes a spin reorientation transition to a planar phase.

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Measurements of the magnetization of DyAgSb 2 reveal a complex system of up to 11 well-defined metamagnetic states for the field applied within the basal plane. Measurements of the magnetization vs the angle the applied field makes with respect to the ͓110͔ axis show the Dy 3ϩ moments are constrained to lie along one of the four ͓110͔ directions within the basal plane. From the angular dependence of the critical fields and plateau magnetizations, the net distribution of the moments may be deduced for each state. Finally, the coupling constants are calculated within the framework of the ''four-position clock model.'' ͓S0163-1829͑99͒04302-7͔