Programmable bias field observed in graded ferromagnetic semiconductor films with broken symmetry

Sining Dong, Yong Lei Wang, Seul Ki Bac, Xinyu Liu, Vitalii Vlasko-Vlasov, Wai Kwong Kwok, Sergei Rouvimov, Sanghoon Lee, Margaret Dobrowolska, Jacek K. Furdyna

Research output: Contribution to journalArticle

Abstract

We report on the observation of a field-induced magnetic bias effect in a Ga0.94Mn0.06As1-yPy thin film with digitally graded phosphorus content. Although phosphorus concentration in the sample is changed in steps from y≈0.03 to y≈0.28, the magnetometry and magnetotransport data display a coherent magnetic response typical for single-layer in-plane magnetized films with cubic and weak [110] uniaxial anisotropy. Unexpectedly, low-temperature planar Hall resistance loops exhibit remarkable asymmetry tunable by application of strong in-plane initial magnetic field HIni. We discuss this unusual memory effect, resembling the magnetization asymmetry in the exchange biased magnetic bilayers, in terms of a unidirectional bias field Hb induced by HIni. We show that such bias field defines the delayed or accelerated nucleation of domains with chiral domain walls performing the magnetization reversal.

Original languageEnglish
Article number074407
JournalPhysical Review Materials
Volume3
Issue number7
DOIs
Publication statusPublished - 2019 Jul 19

ASJC Scopus subject areas

  • Materials Science(all)
  • Physics and Astronomy (miscellaneous)

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    Dong, S., Wang, Y. L., Bac, S. K., Liu, X., Vlasko-Vlasov, V., Kwok, W. K., Rouvimov, S., Lee, S., Dobrowolska, M., & Furdyna, J. K. (2019). Programmable bias field observed in graded ferromagnetic semiconductor films with broken symmetry. Physical Review Materials, 3(7), [074407]. https://doi.org/10.1103/PhysRevMaterials.3.074407