(a) A typical LEED pattern for the 50ML NiO/Fe(001). Primary beam energy is equal to 90 eV. (b) Schematic representation of the samples. (c) Direction of the uniaxial magnetic anisotropy (UA) induced by the oblique deposition is marked by a double-sided arrow.
Hysteresis loops measured for the main crystallographic directions for the as- deposited samples using s polarized light (a) “EB−” system, (b) “EB+” system.
Azimuthal dependence of the coercive field and the hysteresis loop shift measured before (open circles and open squares, respectively) and after field cooling (filled circles and filled squares, respectively). The error bars reflect the noise level during the measurements. The error bars for the “EB−” case are smaller than the data points. The direction of the magnetic field applied during FC is marked by an arrow.
(a) Hysteresis loops for the sample EB+ measured with the s polarized light along the easiest anisotropy direction before (dotted line) and after field cooling performed at 230 °C, showing the exchange bias and training effects. The inset shows a magnification of the region marked by a rectangle (b) Decrease of the exchange bias field for the consecutive hysteresis loops measured after field cooling.
Hysteresis loops for the sample “EB−” measured with the s polarized light along the easiest anisotropy direction before (dotted line) and after field cooling performed at 200 °C, 240 °C, and 255 °C showing the absence of exchange bias and gradual decrease of the coercivity.
The longitudinal (ML) and transversal (MT) components of the magnetization measured for different azimuthal angles (φ) for the “EB−” system after FC.
The reduced remanence (MR/MS) as a function of the azimuthal angle (φ) derived from both branches of the hysteresis loops (squares). The dotted line presents the cosine dependence of the remanence for the simple uniaxial anisotropy while the red (dark grey) solid line for the uniaxial anisotropy accompanied by a small unidirectional term presented separately as the green (light grey) solid circle.
The reduced remanence (MR/MS) as a function of the azimuthal angle (φ) derived from both branches of the hysteresis loops measured before (black squares) and after (red circles) FC. The lines are guides to the eye.
The longitudinal (ML), transversal (MT), and polar (MP) components of the magnetization measured for different azimuthal angles (φ) for the ‘EB+’ system.
CEMS spectra of the sample “1_EB−” (a) and “2_EB−” (b) with the result of the best fit. The spectral components: M, O1, O2 and O3 are offset in the y-axis for clarity.
CEMS spectra of the ‘EB+’ sample with the result of the best fit. The spectral components: M, O1, O2, and O3 are offset in the y-axis for clarity.
The schematic representation of the “EB−” and “EB+” samples, based on the results of the Mössbauer measurements.
Hyperfine parameters derived from the numerical fits of CEMS spectra for “1_EB−,” “2_EB−,” and “EB+” samples. Numbers in parentheses indicate the last digit uncertainty resulting from the least squares fit analysis.
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