REMANENT MAGNETIZATION OF A SIMPLE FERROMAGNET

We have measured the remanent magnetization of single-crystal EuS from 10(-4) to 10(4) sec after removing an applied field. Using a recent model for magnon relaxation on finite domains, the data yield size-scaling exponents of theta = -0.10 +/- 0.02 and zeta = 0.669 +/- 0.004, in excellent agreement with exact theoretical predictions. As a function of temperature, the remanent magnetization is a maximum above the Curie transition, and, for some thermal histories, becomes negative in the ferromagnetic regime. The behavior is consistent with a percolation backbone that is negatively coupled to the finite domains.