Itinerant electron metamagnetism in LaCo${}_9$Si${}_4$

Abstract

The strongly exchange enhanced Pauli paramagnet LaCo${}_9$Si${}_4$ is found to exhibit an itinerant metamagnetic phase transition with indications for metamagnetic quantum criticality. Our investigation comprises magnetic, specific heat, and NMR measurements as well as ab-initio electronic structure calculations. The critical field is about 3.5 T for $H||c$ and 6 T for $H\perp c$, which is the lowest value ever found for rare earth intermetallic compounds. In the ferromagnetic state there appears a moment of about 0.2 $\hat{I}{¼}_B$/Co at the $16k$ Co-sites, but sigificantly smaller moments at the 4d and $16l$ Co-sites.

11 pages, 5 figures, PRB Rapid Communication, in print