Torque magnetometry study of metamagnetic transitions in single-crystalHoNi2B2CatT≈1.9

Abstract

Metamagnetic transitions in single-crystal rare-earth nickel borocarbide HoNi2B2C have been studied at T ≈ 1.9 K with a Quantum Design torque magnetometer. This compound is highly anisotropic with a variety of metamagnetic states at low temperature which includes antiferromagnetic, ferrimagnetic, non-collinear and ferromagnetic-like (saturated paramagnet) states. The critical fields of the transitions depend crucially on the angle θ between applied field and the easy axis [110]. Measurements of torque along the c-axis have been made while changing the angular direction of the magnetic field (parallel to basal tetragonal ab-planes) and with changing field at fixed angle over a wide angular range. Two new phase boundaries in the region of the non-collinear phase have been observed, and the direction of the magnetization in this phase has been precisely determined. At low field the antiferromagnetic phase is observed to be multidomain. In the angular range very close to the hard axis [100] (−6• < ∼ φ < ∼ 6• , where φ is the angle between field and the hard axis) the magnetic behavior is found to be "frustrated" with a mixture of phases with different directions of the magnetization.

Small-angle neutron scattering and magnetization study of HoNi2B2C

“…[27,28]. A recent torque magnetometry study [8] confirms that this phase does not appear for H applied within 1 • of [110], in support of the results of mean-field theory accounting for the crystalline electric field and Ruderman-Kittel-Kasuya-Yosida exchange interaction [30]. For fields applied along the hard c axis, there are no metamagnetic transitions over this field regime.…”

Low-temperature metamagnetic states in single crystal TbNi2B2C studied by torque magnetometry

“…A similar phase was identified for both R = Ho and Er borocarbides by torque magnetometry. 10,11 In summary, torque magnetization measurements basically confirm the metamagnetic phase diagram for TbNi 2 B 2 C determined by longitudinal magnetization measurements, but with the addition of a new phase representing a small rotation of the magnetization at intermediate fields near the hard axis. The torque measurements also clearly indicate that the magnetization of the high field phase for H near the hard axis lies along that axis and is most likely a mixed phase resulting from frustration as observed for the corresponding Er and Ho intermetallic compounds.…”

“…The three closely spaced transition boundaries appear to merge for fields at an angle to the easy axis somewhere between 25°a nd 35°. Torque magnetometry studies, 10,11 which are naturally sensitive only to the component of the magnetization perpendicular to the applied magnetic field, have recently provided new insight to some of these metamagnetic phases for R = Ho, Er and these may clarify the picture for Tb. Here a low temperature ͑T Ϸ 1.9 K͒ study of the metamagnetic phases in TbNi 2 B 2 C by torque magnetometry is presented.…”

Magnetic anisotropy in uranium monosulfide probed by magnetic torque measurements

“…In general, the magnetic torque measurements performed on single crystals are considered as a sensitive probe for studying the magnetic, especially anisotropic properties of solids. This technique has been successfully used to study anisotropic behaviors of superconductors, heavy fermions, and various antiferromagnetic, ferromagnetic, and paramagnetic materials [31][32][33][34][35][36]. Here, we report detailed measurements of the magnetic torque of US single crystals.…”