Magnetic phase diagram of antiferroquadrupole ordering in HoB2C2

Tatsuya Yanagisawa; Terutaka Goto; Yuichi Nemoto; Ryuta Watanuki; Kazuya Suzuki; Osamu Suzuki; Giyuu Kido

doi:10.1103/PhysRevB.71.104416

paper

Magnetic phase diagram of antiferroquadrupole ordering in HoB2C2

arXiv:cond-mat/0501505 · doi:10.1103/PhysRevB.71.104416

Abstract

The magnetic phase diagram for antiferro-quadrupole (AFQ) ordering in tetragonal HoB $_{2}$ C $_{2}$ has been investigated by measurements of elastic constants $C_{11}$ , $C_{44}$ and $C_{66}$ in fields along the basal $x$ - $y$ plane as well as the principal [001]-axis. The hybrid magnet (GAMA) in Tsukuba Magnetic Laboratory was employed for high field measurements up to 30 T. The AFQ phase is no longer observed above 26.3 T along the principal [001] axis in contrast to the relatively small critical field of 3.9 T in fields applied along the basal [110] axis. The quadrupolar intersite interaction of $O_{x y}$ and/or $O_{2}^{2}$ is consistent with the anisotropy in the magnetic phase diagram of the AFQ phase in HoB $_{2}$ C $_{2}$ .

Phys. Rev. B. (2005) in press. approx 8 pages, 10 figures