Ising quantum Hall ferromagnet in magnetically doped quantum wells -: art. no. 266802

We report on the observation of the Ising quantum Hall ferromagnet with Curie temperature T-C as high as 2 K in a modulation-doped (Cd,Mn)Te heterostructure. In this system field-induced crossing of Landau levels occurs due to the giant spin-splitting effect. Magnetoresistance data, collected over a wide range of temperatures, magnetic fields, tilt angles, and electron densities, are discussed taking into account both Coulomb electron-electron interactions and s-d coupling to Mn spin fluctuations. The critical behavior of the resistance spikes at T-->T-C corroborates theoretical suggestions that the ferromagnet is destroyed by domain excitations.