2003/10/31 by A. Aguayo, I. I. Mazin, D. J. Singh · 1 citation
Physics and Astronomy · #Physics of Superconductivity and Magnetism #Quantum and electron transport phenomena #Rare-earth and actinide compounds #cond-mat.mtrl-sci #cond-mat.str-el
paper · pdf · doi:10.1103/physrevlett.92.147201
published as Phys. Rev. Lett. 92, 147201 (2004) · replaced (incorrect version submitted)
arxiv created 2003/11/01 · openalex publication_date 2004/04/05 · arxiv updated 2009/12/01 · openalex created_date 2016/06/24 · openalex updated_date 2026/07/30
Ni3Al and Ni3Ga are closely related materials on opposite sides of a ferromagnetic quantum critical point. The Stoner factor of Ni is virtually the same in both compounds and the density of states is larger in Ni3Ga. Thus in Stoner theory it should be more magnetic, and in local-density approximation (LDA) calculations it is. However, experimentally it is a paramagnet, while Ni3Al is an itinerant ferromagnet. We show that critical spin fluctuations are stronger in Ni3Ga, due to weaker q dependence of the susceptibility, and this effect is enough to reverse the trend. The approach combines LDA calculations with Landau theory and the fluctuation-dissipation theorem using the same momentum cutoff for both compounds. The calculations provide evidence for strong, beyond LDA, spin fluctuations associated with the critical point in both materials, but stronger in Ni3Ga than in Ni3Al.