Detailed magnetization study of quenched random ferromagnets. II. Site dilution and percolation exponents.

摘要: We report the experimental determination of crossover exponent (φ) and percolation critical exponents for magnetization (β p ) spin-wave stiffness (θ) quench-disordered (amorphous) three-dimensional (d=3) dilute Heisenberg ferromagnets. The values φ, θ, β , so obtained, as well those correlation-length V conductivity σ deduced from equalities =φ-(θ/2) σ=(d-2)V +φ, conform very with most accurate theoretical estimates published recently. A comparison presently determined theoretically predicted site or bond on a d=3 crystalline lattice asserts that behavior regular does not get altered in presence quenched randomness if specific-heat system is negative. Consistent Alexander-Orbach conjecture (Golden inquality), fracton dimensionality d¯ percolating cluster at threshold (the s) turns out to be ≈4/3 (σ≤ 2). present results vindicate universality hypothesis.