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Spin fluctuations and the magnetic phase diagram of ZrZn 2

2004; American Physical Society; Volume: 69; Issue: 2 Linguagem: Inglês

10.1103/physrevb.69.020402

1550-235X

I. I. Mazin, David J. Singh,

Advanced Condensed Matter Physics

The magnetic properties of the weak itinerant ferromagnet ${\mathrm{ZrZn}}_{2}$ are analyzed using Landau theory based on a comparison of density-functional calculations and experimental data as a function of field and pressure. We find that the magnetic properties are strongly affected by the nearby quantum critical point, even at zero pressure; local-density approximation LDA calculations neglecting quantum critical spin fluctuations overestimate the magnetization by a factor of $\ensuremath{\approx}3.$ Using renormalized Landau theory, we extract pressure dependence of the fluctuation amplitude. It appears that a simple scaling based on the fluctuation-dissipation theorem provides a good description of this pressure dependence.