Ferromagnetism in the hexagonal cage-like compounds Sm₆(Mo,W)₄Al₄₃

We will report results for single crystals of Sm₆T₄Al₄₃ (T=Mo,W) that were synthesized using a molten Al flux. Powder X-Ray diffraction measurements show that both compounds crystallize in the hexagonal Ho₆Mo₄Al₄₃ structure with lattice constants near a = 10.97 Å and c = 17.67 Å, as reported previously [1]. As for other compounds in this structure, the electrical transport data exhibit a weak temperature dependence due to significant disorder scattering, likely associated with atomic site interchange. The temperature dependent magnetic susceptibility and heat capacity further show that ferromagnetic ordering emerges from a weakly paramagnetic state near T_C = 15 and 16 for the Mo and W variants, respectively. We will discuss these results in the context of other Sm-based intermetallics, where the f-state and the associated magnetism is strongly influenced by van Vleck physics.

[1] S. Niemann et al., Journal of Solid State Chemistry Vol 116 Issue 1, 0022-4596 (1995).

Authours:
Ryan E. Baumbach, Lucas Nelson, Kaya Wei and Juan Jose Mejia Marin