Ferromagnetic Epitaxial μ-Fe2O3 on β-Ga2O3: A New Monoclinic Form of Fe2O3

John S. Jamison, Brelon J. May, Julia I. Deitz, Szu Chia Chien, David W. McComb, Tyler J. Grassman, Wolfgang Windl, Roberto C. Myers

Research output: Contribution to journalArticlepeer-review

5 Scopus citations


Here we demonstrate a new monoclinic iron oxide phase (μ-Fe2O3), epitaxially stabilized by growth on (010) β-Ga2O3. Density functional theory (DFT) calculations find that the lattice parameters of freestanding μ-Fe2O3 are within ∼1% of those of β-Ga2O3, and that its energy of formation is comparable to that of naturally abundant Fe2O3 polytypes. A superlattice of μ-Fe2O3/β-Ga2O3 is grown by plasma assisted molecular beam epitaxy, with resulting high-resolution X-ray diffraction (XRD) measurements indicating that the μ-Fe2O3 layers are lattice-matched to the substrate. The measured out-of-plane (b) lattice parameter of 3.12 ± 0.4 Å is in agreement with the predicted lattice constants and atomic-resolution scanning transmission electron microscopy (STEM) images confirm complete registry of the μ-Fe2O3 layers with β-Ga2O3. Finally, DFT modeling predicts that bulk μ-Fe2O3 is antiferromagnetic, while the interface region between μ-Fe2O3 and β-Ga2O3 leads to ferromagnetic coupling between interface Fe3+ cations selectively occupying tetrahedral positions. Magnetic hysteresis persisting to room temperature is observed via SQUID measurements, consistent with the computationally predicted interface magnetism.

Original languageEnglish
Pages (from-to)4205-4211
Number of pages7
JournalCrystal Growth and Design
Issue number8
StatePublished - 7 Aug 2019


Dive into the research topics of 'Ferromagnetic Epitaxial μ-Fe2O3 on β-Ga2O3: A New Monoclinic Form of Fe2O3'. Together they form a unique fingerprint.

Cite this