New Type of the Domain-Redistribution at Low Magnetic Fields in Phase II of CeB6

作者：Kunimori Keisuke^*; Sera Masafumi; Tanida Hiroshi; Matsumura Takeshi; Iga Fumitoshi

来源：Journal of the Physical Society of Japan, 2012, 81(10): 104706.

DOI：10.1143/JPSJ.81.104706

• CeB6
• quadrupole order
• octupole interaction
• antiferro-quadrupole ordered phase
• domain

We performed the detailed investigation of the magnetization (M) of CeB6 at low magnetic fields in the O-xy-type antiferro-quadrupole (AFQ) ordered phase II to clarify the mechanism of the domain redistribution by magnetic field. Although M in phase II is isotropic above similar to 1 kOe, it is anisotropic at lower magnetic fields and the magnetic field of the domain redistribution (H-c(IIA-IIB)) is highly anisotropic. M-[001] %26lt; M-[110] %26lt; M-[111] and H-c(IIA-IIB[001]) %26gt; H-c(IIA-IIB[110]) %26gt; H-c(IIA-IIB[111]). Here, M-[001] and H-c(IIA-IIB[001]) are M and H-c(IIA-IIB) for H parallel to [001], etc. respectively. Although there exist three domains of O-xy-, O-yz-, and O-zx-AFQ ordered states at H = 0 as in a usual AF magnet, these domains are coupled in magnetic fields and the single domain state is formed by the linear combination of O-xy, O-yz, and O-zx quadrupole moments above H-c(IIA-IIB) through the magnetic field induced higher order T-xyz-antiferro-octupole (AFO) interaction. The domain redistribution takes place due to the competition between the small tetragonal lattice distortion stabilized by the O-xy-type AFQ order at H = 0 and the Zeeman interaction. For H parallel to [001], M is smallest and H-c(IIA-IIB) is highest because only the O-xy-domain couples with the Txyz-AFO moment inducing the effective ferromagnetic interaction but the two domains of O-yz and O-zx are not. For H parallel to [111], M is largest below similar to 1 kOe and H-c(IIA-IIB) is lowest because the T-xyz-AFO moment is induced in all the three domains and each of O-xy, O-yz, and O-zx domain changes continuously to the (O-yz + O-zx + O-xy)/root 3 single domain with increasing magnetic field. The coefficients of the linear combination of three domains gradually changes with magnetic field through the magnetic field induced T-xyz-AFO moment. This type of the continuous domain redistribution is different from that in the usual antiferro-magnet, where there does not exist the coupling among the different domains.

• 出版日期2012-10