Published in Physical Review Letters, Volume 87, Issue 2, June 21, 2001, pages 027001.1-027001.4.
Copyright © 2001 American Physical Society. This article may be downloaded for personal use only. Any other use requires prior permission of the author and the American Physical Society. The following article appeared in Physical Review Letters and may be found at http://dx.doi.org/10.1103/PhysRevLett.87.027001.
NOTE: At the time of publication, the author Karl Saunders was not yet affiliated with Cal Poly.
Ferromagnetic order in superconductors can induce a spontaneous vortex (SV) state. For external field H = 0, rotational symmetry guarantees a vanishing tilt modulus of the SV solid, leading to drastically different behavior than that of a conventional, external-field-induced vortex solid. We show that quenched disorder and anharmoinc effects lead to elastic moduli that are wave-vector dependent out to arbitrarily long length scales, and non-Hookean elasticity. The latter implies that for weak external fields H, the magnetic induction scales universally like B(H)∼B(0)+cHα, with α≈0.72. For weak disorder, we predict the SV solid is a topologically ordered glass, in the “columnar elastic glass” universality class.