Sm2Co17-Pressure

The compound Sm₂Co₁₇ displays magnetic properties amenable to permanent magnet applications owing to both the 3d electrons of Co and the 4f electrons of Sm. The long-standing description of the magnetic interactions between the Sm and Co ions implies a truly ferromagnetic configuration, but some recent calculations challenge this axiom, suggesting at least a propensity for ferrimagnetic behavior. We have used high-pressure synchrotron x-ray techniques to characterize the magnetic and structural properties of Sm₂Co₁₇ to reveal a robust ferromagnetic state. The local Sm moment is at most weakly affected by compression, and the ordered moments show a surprising resilience to volumetric compressions of nearly 20%. Density functional theory calculations echo the magnetic robustness of Sm₂Co₁₇, and predict that the Co moment should stay robust, due to the majority spin band edge remaining below the Fermi level, up to pressures near 70 GPa.

This work appeared in Physical Review B 90, 104408 (2014).