(Color online) Main panel shows the overall magnetic in-plane hysteresis m vs μ 0H of the magnetic heterostructure at room temperature. (a) Schematic view of the sample structure. (b) Wide angle X-ray diffraction data showing CoPt (111), NiFe (111), and (200) peaks and the Si (400) substrate peak. (c) Minor magnetic hysteresis loop m vs μ 0H measured at room temperature after saturation in a field of 0.3 T.
Normalized minor magnetic hysteresis loops m/ms vs μ 0 H for various orientations of the in-plane magnetic field with respect to a fixed reference direction of the sample changing from 0° (a) to 30° (b), 60° (c), and 90° (d), respectively.
(Color online) Main panel shows the magnetic minor loop hysteresis m vs μ 0H with specific highlighted magnetization states A, B, C, D, and E on the descending branch of the loop. Panel A shows the PNR data, (triangles) and (circles) vs , measured at the magnetization state A of the hysteresis loop. Panel B shows (triangles) and (circles) vs together with the spin flip reflectivity R SF vs (squares) at the magnetization state B. Panels C, D, and E show the same set of reflectivities for the corresponding magnetization states C, D, and E.
(Color online) Activity chart visualizing the logical structure of the data analysis which involves PNR, magnetometry, magneto-transport measurements, and development of models for the magnetization reversal mechanisms and their quantitative testing.
(Color online) Main panel shows the magnetic minor loop hysteresis m vs μ 0H (up triangles) with a fit (line) of an empirical function (see text). Open circles show the field dependence of the electric resistance. Solid line with minimum marked by right vertical dashed line is the result of the best fit of the uniform rotation model. Squares are the results of a single parameter fit of the exchange spring model and connected by a spline. The left vertical dashed line indicates the onset of the exchange spring behavior determined by the bending field. Inset (a) shows the descending branch of m vs μ 0H (down triangles) up to the high field irreversibility region. The line is a best fit of the asymptotic -dependence predicted by the analytic exchange spring model. Inset (b) shows calculated from numerical solutions of the Euler equation for specific magnetic fields = 0.55, 0.62, 0.74, 1.02, 1.50, and 2.31 mT. The figure in the upper right corner of the main panel is a sketch of the hard layer/soft layer component of the heterostructure. The lower two arrows represent stationary local magnetization of the CoPt pinning layer. The upper 10 arrows indicate the in-plane rotation of local magnetization of NiFe layer. is the angle of the local magnetization (dashed back pointing arrow) with respect to the direction of the pinning magnetization (dashed horizontal arrow). The vertical line is the z-axis quantifying the depth coordinate in the NiFe layer starting at z = 0 (CoPt/NiFe interface) and ending at z = t = 450 nm, thickness of the NiFe film.
Parameters entering the fit of the MR branch associated with uniform rotation of the top NiFe layer and the exchange spring behavior of the bottom NiFe layer, respectively. Parameters are indicated as free or fixed.
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