Fully Compensated Synthetic Antiferromagnets with Pronounced Anomalous Hall and Magneto-Optical Responses

Engineering Spin Configurations of Synthetic Antiferromagnet by Controlling Long‐Range Oscillatory Interlayer Coupling and Neighboring Ferrimagnetic Coupling

“…In our experiments, the H ex was obtained by measuring the horizontal offset of the minor AHE loop corresponding to the [Co/Pt/Co] layer (Figure S3, Supporting Information), which was positive for the Co 75 Tb 25 SAFs and negative for the Co 65 Tb 35 SAFs in the t Ru range of macroscopic antiferromagnetic interlayer coupling. [ 27 ] The experimental values of J ex and H ex as a function of t Ru for both the Co 65 Tb 35 and Co 75 Tb 25 series of samples are summarized in Figure 2d. The orange dashed line shows the best fitting using the equation $${J_{ex}} \propto J\sin (\varphi + 2\pi {t_{{\rm{Ru}}}}{\rm{/}}\lambda ){\rm{/}}t_{{\rm{Ru}}}^p$$, where J, φ , λ, and p represent the exchange coupling strength, system‐specific variable, oscillation period, and decay order, respectively.…”

“…For instance, in a conventional magnetizationcompensated SAF, the anomalous Hall resistance R AH of the upper and lower FM layers usually counteracts each other and merges into a reduced output signal, which is unfavorable for the magnetic states reading. [26,27] A much larger coercivity is found for FIMs near the magnetization compensation point, leading to a large critical switching current density or a larger in-plane assistant magnetic field for deterministic perpendicular SOT switching. [28,29] Therefore, it is urgent to explore the possibility of combining multiple manipulation methods to achieve efficient engineering of spin configurations in the SAFs composed of FIMs and FMs, which can supply a way to integrate the advantages of FM, FIM, and AFM materials into one SAF heterostructure for realistic spintronic applications.…”

“…It is worth mentioning that the simultaneous realization of magnetization compensation and R AH enhance-ment for the Tb-dominated Co 65 Tb 35 samples with t Ru in the range of 1.2 to 1.5 nm is of particular interest for the realistic antiferromagnetic device applications, which cannot be realized in the Co 75 Tb 25 series of samples and conventional SAFs.The IEC strength can be quantitatively characterized by the intrinsic exchange field H ex or the coefficient J ex = -H ex M s t. Here, M s = 710 emu cm -3 and t = 1.1 nm are the saturation magnetization and thickness of the [Co/Pt/Co] layer, respectively. In our experiments, the H ex was obtained by measuring the horizontal offset of the minor AHE loop corresponding to the [Co/Pt/Co] layer (FigureS3, Supporting Information), which was positive for the Co 75 Tb 25 SAFs and negative for the Co 65 Tb 35 SAFs in the t Ru range of macroscopic antiferromagnetic interlayer coupling [27]. The experimental values of J ex and H ex as a function of t Ru for both the Co 65 Tb 35 and Co 75 Tb 25 series of samples are summarized in Figure2d.…”

Systematic Control of Ferrimagnetic Skyrmions via Composition Modulation in Pt/Fe1–xTbx/Ta Multilayers

“…The magnetic properties of ferrimagnets made of transition metal (TM) and rare earth (RE) elements can be readily tuned. For example, the net saturation magnetization ( M S ) and the anisotropy constant ( K u ) can be tuned via changing their relative chemical compositions. − Note that the key parameters of skyrmions are determined by the material specific parameters of multilayers, including the exchange constant ( A ), iDMI coefficient ( D ), film thickness ( t F ), and anisotropy constant ( K u ). , This warrants a tailoring of ferrimagnetic skyrmions with desired parameters to be made. − This aspect is, however, not being examined, which motivates the present study.…”

Voltage control of magnetic order in RKKY coupled multilayers

“…Synthetic AFMs, while not intrinsically compensated, can be engineered to share many of the same advantages as crystalline AFMs. By controlling the relative thickness of the constituent FM layers, synthetic AFMs can have zero stray fields ( 21 ), thereby limiting cross-talk between bits and increasing bit density ( 7 ). While the exchange interaction in synthetic AFMs is much weaker than in crystalline AFMs and, therefore, more susceptible to external fields, synthetic AFMs can still be engineered to have stable AFM coupling up to several tesla ( 7 ).…”