Evidence for Skyrmions and Single Spin Flips in the Integer Quantized Hall Effect

We have employed tilted-field magnetotransport measurements of the energy gap for the odd-integer quantized Hall states at Landau level filling factors $\nu =1, 3, \mathrm{and} 5$ to determine the spin of thermally excited quasielectron-quasihole pairs. At $\nu =1\mathrm{}$ our data show that as many as 7 electron spin flips accompany such excitations, while at $\nu =3\mathrm{} \mathrm{and} 5$ apparently only a single spin flips. These results lend support to the recent suggestions that "Skyrmionic" quasiparticles are the lowest-lying charged excitations of the fully polarized $\nu =1\mathrm{}$ quantum Hall fluid but are not at the higher odd-integer fillings.