Spatially correlated disorder in self-organized precursor magnetic nanostructures

Abstract

We study the scaling behavior of the characteristic length of precursor magnetic nanostructures above the Curie temperature with the correlation length of quenched-in disorder. We found that the modulation length of the nanostructures ¿ follows the scaling law ¿~D¯--v, where D¯ is the average size of the magnetized regions in the material. The scaling behavior of the average size of these regions, D¯, with the correlation length of the disorder, s, depends on the properties of the disorder. For Gaussian disorder, we find that D¯ scales with the disorder correlation length as D¯~sa/2, where a is the exponent of the leading term of the pair correlation function of the disorder in the limit r¿0, G(r)˜e[1-(1/a)(r/s)a]. These results are quite general and applicable to other systems, e.g., ferroelectric precursors, independent of the nature of the long-range dipolar forces.