Affiliation:
1. Department of Mechanical & Materials Engineering University of Nebraska‐Lincoln 900 N 16th Street, W342 NH Lincoln NE 68588 USA
2. Department of Physics and Astronomy and the Nebraska Center for Materials and Nanoscience University of Nebraska‐Lincoln 855 N 16th Street Lincoln NE 68588 USA
3. Components Research Intel Corporation 2501 NE Century Boulevard Hillsboro 97124 OR USA
4. Laser Center University of Latvia Jelgavas St 3 Riga LV‐1004 Latvia
Abstract
AbstractChromia (Cr2O3) is a magnetoelectric oxide that permits voltage‐control of the antiferromagnetic (AFM) order, but it suffers technological constraints due to its low Néel Temperature (TN ≈307 K) and the need of a symmetry‐breaking applied magnetic field to achieve reversal of the Néel vector. Recently, boron (B) doping of Cr2O3 films led to an increase TN >400 K and allowed the realization of voltage magnetic‐field free controlled Néel vector rotation. Here, the impact of B doping is directly imaged on the formation of AFM domains in Cr2O3 thin films and elucidates the mechanism of voltage‐controlled manipulation of the spin structure using nitrogen‐vacancy (NV) scanning probe magnetometry. A stark reduction and thickness dependence of domain size in B‐doped Cr2O3 (B:Cr2O3) films is found, explained by the increased germ density, likely associated with the B doping. By reconstructing the surface magnetization from the NV stray‐field maps, a qualitative distinction between the undoped and B‐doped Cr2O3 films is found, manifested by the histogram distribution of the AFM ordering, that is, 180° domains for pure films, and 90° domains for B:Cr2O3 films. Additionally, NV imaging of voltage‐controlled B‐doped Cr2O3 devices corroborates the 90° rotation of the AFM domains observed in magnetotransport measurement.
Funder
National Science Foundation