Marked Change in the Ground State of CeRu2Al10 Induced by Small Amount of Rh Substitution

• Published in: Journal of the Physical Society of Japan 2013-05, Vol.82 (5), p.054709-054709-5
• Main Authors: Kondo, Akihiro, Kindo, Koichi, Kunimori, Keisuke, Nohara, Hiroki, Tanida, Hiroshi, Sera, Masafumi, Kobayashi, Riki, Nishioka, Takashi, Matsumura, Masahiro
• Format: Article
• Language: English
• ISSN: 0031-9015; 1347-4073
• DOI: 10.7566/JPSJ.82.054709

We have investigated the marked change in the magnetic properties of CeRu 2 Al 10 induced by a small amount of Rh substitution [Ce(Ru 0.95 Rh 0.05 ) 2 Al 10 ]. The magnetic susceptibility along the $a$-axis ($\chi_{a}$) shows a large decrease with decreasing temperature after showing a sharp peak at $T_{0}=24$ K and the high field magnetization for the magnetic field along the $a$-axis exhibits a spin-flop transition at ${\sim}13$ T. These indicate that the antiferromagnetic (AFM) order where the AFM moment is parallel to the $a$-axis takes place, which is consistent with the anisotropy of $\chi_{a}>\chi_{c}>\chi_{b}$ in the paramagnetic region, being different from the AFM order in CeRu 2 Al 10 . These results were analyzed by mean field calculation for the two-sublattice model using the crystalline electric field level scheme by Strigari et al. [Phys. Rev. B 86 (2012) 081105]. On the basis of both experimental and calculated results, we conclude that, by a small amount of Rh substitution with one extra $4d$ electron, the large $c$--$f$ hybridization along the $a$-axis, leading to the unusual ground state of CeRu 2 Al 10 , is markedly suppressed and the Ce ion in a Rh-substituted sample becomes close to the normal localized magnetic ion.