Angular dependence of metamagnetic transitions in HoNi2B2C

Abstract

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 remaining perpendicular to the crystallographic c axis, reveal three metamagnetic 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] direction. The locally saturated moments for fields between H-ci (i = 1, 2, 3) also manifest angular dependences that are consistent with combinations of local moments along [110] axes. Analysis of these data lead us to infer that the net distribution of moments is (up arrow down arrow up arrow down arrow up arrow down arrow) for H up arrow up arrow-->) for H-c2 up arrow up arrow-->) for H-c2 H-c3.