Dielectric Polarization Measurements on the Antiferromagnetic Triangular Lattice System CuFeO₂ in Pulsed High Magnetic Fields

抄録

Dielectric polarization parallel to the [110] direction of a single crystal of the triangular lattice antiferromagnet CuFeO₂ has been measured by a pyroelectric method in pulsed high magnetic fields up to 43 T applied along the [001] direction. No distinct spontaneous dielectric polarization P is detected in the fourth field-induced phase with a noncollinear spin structure and 4-, 5-, and 3-sublattice phases with commensurate collinear spin structures. Among five magnetic phases that appear in magnetic fields, a finite P is observed only in the first field-induced phase with the incommensurate noncollinear spin structure. We also confirmed that P in the first field-induced phase is predominantly oriented within the (001) plane. A strong history dependence has been observed in P, and is interpreted in terms of the alignment and repopulation of magnetic Q-domains. The experimental technique for measuring P in pulsed high magnetic fields is described in detail.