Magnetic Vacancy Percolation in Dilute Antiferromagnets

TL;DR

This study investigates magnetic vacancy percolation in dilute antiferromagnets, demonstrating stable long-range order at the vacancy threshold and revealing fractal scattering structures through neutron experiments.

Contribution

It provides experimental evidence for stable long-range magnetic order at the vacancy percolation threshold in a dilute antiferromagnet, confirming simulation predictions.

Findings

Stable long-range order observed up to 6.5 T

Percolation threshold exhibits fractal scattering patterns

Experimental results support simulation boundaries

Abstract

Neutron scattering experiments at the magnetic vacancy percolation threshold concentration, x_v, using the random-field Ising crystal Fe(0.76)Zn(0.24)F2, show stability of the transition to long-range order up to fields H=6.5 T. The observation of the stable long-range order corroborates the sharp boundary observed in computer simulations at x_v separating equilibrium critical scattering behavior at high magnetic concentration from low concentration hysteretic behavior. Low temperature H>0 scattering line shapes exhibit the dependence on the scattering wavevector expected for percolation threshold fractal structures.