ANGULAR-DEPENDENCE OF METAMAGNETIC TRANSITIONS IN HONI2B2C

Detailed measurements of M(2 K, H, theta) of HoNi2B2C, where theta is the angle that the applied field H makes with the [110] axis while rem aining perpendicular to the crystallographic c axis, reveal three meta magnetic transitions with angular dependences H-c1 = (4.1 +/- 0.1 kG)/ cos(theta), H-c2 = 8.4 +/- 0.2 kG/cos(phi), and H-c3 = (6.6 +/- 0.2 kG )/sin(phi), where phi = theta-45 is the angle from the [100] axis. The high-field saturated moment, M(sat) approximate to 10 mu(B)cos theta is consistent with the local moments being confined to the [110] direc tion. The locally saturated moments for fields between H-ci (i = 1, 2, 3) also manifest angular dependences that are consistent with combina tions of local moments along [110] axes. Analysis of these data lead u s to infer that the net distribution of moments is (up arrow down arro w up arrow down arrow up arrow down arrow) for H < H-c1, (up arrow up arrow down arrow up arrow up arrow down arrow) for H-c1 < H <H-c2, (up arrow up arrow-->up arrow up arrow-->) for H-c2 < H < H-c3, and (up a rrow up arrow up arrow up arrow up arrow up arrow) for H > H-c3.