Quantum Hall Ferromagnet in Magnetically-Doped Quantum Wells
T. Andrearczyk a,b , J. Jaroszyński a,b , J. Wróbel a , G. Karczewski a , T. Wojtowicz a , E. Papis c , E. Kamińska c , A. Piotrowska c , D. Popović b and T. Dietl a
a Institute of Physics, Polish Academy of Sciences, al. Lotników 32/46, 02-668 Warszawa, Poland,
b National High Magnetic Field Laboratory, Florida State University, 1800 E. Paul Dirac Dr., Tallahassee, FL 32310, USA,
c Institute of Electron Technology, al. Lotników 32/46, 02-668 Warszawa, Poland
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The article reviews our recent studies on quantum Hall ferromagnetism in diluted magnetic semiconductors. We carried out magnetoresistance studies on modulation-doped, gated heterostructures of (Cd,Mn)Te/(Cd,Mg)Te:I. We put into evidence the formation of Ising quantum Hall ferromagnet with Curie temperature T C as high as 2K. Quantum Hall ferromagnetism is manifested by anomalous magnetoresistance maxima. Moreover, magnitude of these spikes depends dramatically on the history of the sample, shows hysteresis when either magnetic field or gate voltage are swept, stretched-exponential time evolution characteristic of glassy systems, and strong Barkhausen noise. Our study suggests that these metastabilities stem from the slow dynamics of ferromagnetic domains.
DOI: 10.12693/APhysPolA.104.93
PACS numbers: 73.43.Nq, 72.25.Dc, 73.61.Ga, 75.50.Pp