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

We have employed tilted-field magneto-transport measurements of the energy gap for the odd-integer quantized Hall states at Landau level filling factors $\nu = 1$,3 and 5 to determine the spin of thermally excited quasielectron-quasihole pairs. At $\nu = 1$ our data show that as many as 7 electron spin flips accompany such excitations, while at $\nu =3$ 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 $\nu = 1$ quantum Hall fluid but are not at the higher odd-integer fillings.