Abstract
Specific heat, magnetization, and electrical resistivity have been studied on single crystalline samples of . These results clearly indicate that undergoes an antiferromagnetic transition at approximately 3.4 K under a zero magnetic field. The magnetic field induces another ordered phase when the field is applied along the or directions of the crystallography, whereas we have not found another ordered phase along the direction of the field. The specific heat and the magnetization along three directions of the field reveal an easy-plane type magnetic anisotropy even in the antiferromagnetic phase. The magnetic structures of the ordered phases are discussed from the standpoint of macroscopic measurement, which results in a helical magnetic structure as a reasonable scenario. A large Sommerfeld coefficient of the specific heat and squared-temperature dependence of the electrical resistivity strongly suggest construction of the heavy-fermion state in , while the influence of the frustration is hardly found.
- Received 3 August 2017
- Revised 22 June 2018
DOI:https://doi.org/10.1103/PhysRevB.98.035131
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