Near to filling fraction $\nu =1,$ the quantum Hall ferromagnet contains multiple Skyrmion spin excitations. This multi-Skyrmion system has a tremendously rich quantum-critical structure. This is simplified when Skyrmions are pinned by disorder. We calculate the nuclear relaxation rate in this case and compare the result with experiment. We discuss how such measurements may be used to further probe the quantum-critical structure of the multi-Skyrmion system.

• Received 9 December 1999

DOI:https://doi.org/10.1103/PhysRevB.61.R16299