Large ferroquadrupole moment induced in the octupole-ordered CeLaB revealed by high-resolution X-ray diffraction

Inami, Toshiya; Michimura, Shinji*; Hayashi, Yuya*; Matsumura, Takeshi*; Sera, Masafumi*; Iga, Fumitoshi*

Physical Review B, 90(4), p.041108_1 - 041108_5, 2014/07

https://doi.org/10.1103/PhysRevB.90.041108

We carried out a high-resolution X-ray diffraction experiment on CeLaB. This compound exhibits antiferro-octupole order (AFO) below = 1.4 K, and it is theoretically suggested that ferroquadrupole moments and a resultant rhombohedral deformation are induced in the AFO phase. We observe the splitting of Bragg reflections below and find that the unit cell is rhombohedral with the elongated [111] axis. We also precisely evaluate the magnitude of the induced quadrupole moments from the obtained shear strain and find that the quadrupole moments are not reduced in the AFO phase.