Magnetization and Magnetoresistance of CeRu2Al10 under High Magnetic Fields along $c$-Axis

• Published in: Journal of the Physical Society of Japan 2011-01, Vol.80 (1), p.013701-013701-4
• Main Authors: Kondo, Akihiro, Wang, Junfeng, Kindo, Koichi, Takesaka, Tomoaki, Ogane, Yuta, Kawamura, Yukihiro, Nishioka, Takashi, Tanaka, Daiki, Tanida, Hiroshi, Sera, Masafumi
• Format: Article
• Language: English
• Subjects: Condensed matter: electronic structure, electrical, magnetic, and optical properties; Domain effects, magnetization curves, and hysteresis; Electronic conduction in metals and alloys; Electronic transport in condensed matter; Exact sciences and technology; Galvanomagnetic and other magnetotransport effects; Magnetic properties and materials; Magnetization curves, magnetization reversal, hysteresis, barkhausen and related effects; Physics
• ISSN: 0031-9015; 1347-4073
• DOI: 10.1143/JPSJ.80.013701

We have studied the magnetization and magnetoresistance of CeRu 2 Al 10 in the applied magnetic field $H$ along the $c$-axis up to ${\sim}55$ T. The magnetization $M$ at low temperatures shows an $H$-linear increase with a small slope of $M/H$ than that for $H\parallel \text{$a$-axis}$ up to ${\sim}55$ T after showing a small anomaly at $H^{*}\sim 4$ T, which indicates that the critical field to the paramagnetic phase $H_{c}^{\text{p}}$ is higher than 55 T for $H\parallel \text{$c$-axis}$. The magnetization curves for $H$ $\parallel$ $a$- and $c$-axes below the antiferro magnetic (AFM) transition temperature $T_{0}$ behave as if the magnetic anisotropy in the AFM-ordered phase is small, although there exists a large magnetic anisotropy in the paramagnetic phase, which favors the easy magnetization axis along the $a$-axis. On the other hand, very recently, Khalyavin et al. have reported that the AFM order where the magnetic moment is parallel to the $c$-axis takes place below $T_{0}$ [Phys. Rev. B 82 (2010) 100405]. These results indicate that the AFM order in this compound is not a simple one. The longitudinal magnetoresistance for $H\parallel \text{$c$-axis}$ at low temperatures shows no anomaly originating from the phase transition, but shows oscillations below 4.2 K. This oscillatory behavior below 4.2 K originates from the Shubnikov--de Haas oscillations, from which the cross section of the Fermi surface normal to the $c$-axis is estimated to be ${\sim}1.0\times 10^{14}$ cm -2 , with no large effective mass. This is the first direct evidence of the existence of the Fermi surface below $T_{0}$.