Structural and magnetic transitions in the crystalline approximant Cd6Sm.

R. Tamura (1) , Y. Muro , T. Hiroto , H. Yaguchi , G. Beutier (2) , T. Takabatake

1 Tokyo University Sci. Dept. Sci. & Technol.
2 SIMaP - Science et Ingénierie des Matériaux et Procédés

Electrical resistivity, specific heat, magnetic susceptibility, and magnetization of the crystalline approximant Cd6Sm are investigated in a temperature range 1.8-300 K. Both structural and magnetic transitions are clearly evidenced. A sharp structural phase transition is observed at T-c = 179 K in the electrical resistivity as well as in the specific heat, which is attributed to orientational ordering of the Cd-4 tetrahedron located at the center of the icosahedral cluster. In addition, three successive magnetic transitions are found at T-M1 = 12.5, T-M2 = 10.2, and T-M3 = 6.5 K. The anomaly at T-M1 is attributed to an antiferromagnetic transition, whereas those at T-M2 and T-M3 are to ferrimagnetic transitions. The observation of the ferrimagnetic orders indicates that (pseudo) icosahedra made of localized Sm spins have a nonzero net magnetic moment, and the moments of the magnetic clusters form a long-range magnetic order.

Domaines: Matériaux

R. Tamura, Y. Muro, T. Hiroto, H. Yaguchi, G. Beutier, et al.. Structural and magnetic transitions in the crystalline approximant Cd6Sm.. Physical Review B: Condensed Matter and Materials Physics (1998-2015), 2012, 85 (1), pp.014203. ⟨10.1103/PhysRevB.85.014203⟩. ⟨hal-00728140⟩