We study the \nu=5/2 even-denominator fractional quantum Hall effect (FQHE) over a wide range of magnetic (B) field in a heterojunction insulated gate field-effect transistor (HIGFET). The electron density can be tuned from n=0 to 7.6 \times 10^{11} cm^{-2} with a peak mobility \mu = 5.5 \times 10^6 cm^2/Vs. The \nu=5/2 state shows a strong minimum in diagonal resistance and a developing Hall plateau at magnetic fields as high as 12.6T. The strength of the energy gap varies smoothly with B-field. We interpret these observations as strong evidence for a spin-polarized ground state at \nu=5/2.
@article{arxiv.cond-mat/0103144,
title = {Experimental Evidence for a Spin-Polarized Ground State in the \nu=5/2 Fractional Quantum Hall Effect},
author = {W. Pan and H. L. Stormer and D. C. Tsui and L. N. Pfeiffer and K. W. Baldwin and K. W. West},
journal= {arXiv preprint arXiv:cond-mat/0103144},
year = {2009}
}