Antiferromagnetic interlayer coupling in Pt/Co multilayers with perpendicular anisotropy

Abstract

By using one ultrathin NiO layer to replace the Pt capping layer in the Co/Pt multilayer with perpendicular anisotropy, we present direct evidence for the existence of antiferromagnetic interlayer coupling between the Co layers through the Pt layers thicker than 24 Å. The NiO capping layers play two key roles in the observation of antiferromagnetic interlayer coupling. One is the manipulation of the coercivity of the Co layer in contact with the NiO layer, the other is the enhancement of the electron reflectivities at the Co/Pt interfaces via the specular scattering effect at the Co-NiO interface. The thermal variation in the magnetization of the Co layer also plays an important role in the observed antiferromagnetic coupling due to its strong effect on the phase of electron reflectivity at the Co/Pt interfaces. The magnetization-dependent phase can lead to the ferromagnetic-antiferromagnetic transition of the interlayer coupling at high temperature. All these factors are combined together to realize the direct observation of antiferromagnetic interlayer coupling in the Co/Pt multilayer with perpendicular anisotropy.

Impact of buffer layer and Pt thickness on the interface structure and magnetic properties in (Co/Pt) multilayers

“…The coercive fields measured for the samples grown on Pt are close to 200 Oe, i.e. similar to or slightly smaller than the values reported by other authors for these Co and Pt thicknesses [27][28][29]34]. Some studies have reported on the nonmonotonic/oscillatory variation of H c as a function of t Pt , which has been attributed to the oscillatory interlayer coupling in (Co / Pt) multilayers [27,28].…”

Self-Modulated Magnetism in Two-Dimensional Ferromagnet Fe3GeTe2 Induced by Ambient Effects

“…Similar closed double square-shaped hysteresis loops are observed for antiferromagnetically coupled MHP between two ferromagnetic layers, 61 and for antiferromagnetically coupled multilayers, open or closed double square-shaped hysteresis loops can be obtained by tuning interlayer exchange coupling. 64,65 Therefore, we infer that closed double square-shaped hysteresis loops in Figure 4b are related to antiferromagnetic coupling between FM 1 and FM 2, which induces the magnetic moments of FM 1 to reverse at a small positive magnetic field.…”

Interlayer exchange coupling and magnetic reversal in Co/Pt multilayers

“…Even though the existence of AF coupling across the Pt spacer had been predicted theoretically [4], extensive studies on [Co/Pt] n multilayers with perpendicular anisotropy had just revealed the FM interlayer coupling [5][6][7]. Our recent investigations on the Co(4Å)/Pt(t PtÅ )/[Co(4Å)/Pt(6Å)] n multilayers with spin-valve configuration had reported the AF interlayer coupling through the Pt spacers [8][9][10][11][12]. The IEC oscillates as a function of Pt spacer thickness and repetition number at AF coupling background.…”