Temperature-dependent interlayer exchange coupling strength in synthetic antiferromagnetic [Pt/Co]₂/Ru/[Co/Pt]₄multilayers

Abstract

In this work, we experimentally investigated the thermal stability of the interlayer exchange coupling field (H ex ) and strength (−J iec ) in synthetic antiferromagnetic (SAF) structure of [Pt(0.6)/Co(0.6)] 2 /Ru(t Ru )/[Co(0.6)/Pt(0.6)] 4 multilayers with perpendicular anisotropy. Depending on the thickness of the spacing ruthenium (Ru) layer, the observed interlayer exchange coupling can be either ferromagnetic or antiferromagnetic. The H ex were studied by measuring the magnetization hysteresis loops in the temperature range from 100 K to 700 K as well as the theoretical calculation of the −J iec . It is found that the interlayer coupling in the multilayers is very sensitive to the thickness of Ru and temperature. The H ex exhibits either a linear or a non-linear dependence on the temperature for different thickness of Ru. Furthermore, our SAF multilayers show a high thermal stability even up to 600 K (H ex = 3.19 kOe, −J iec = 1.97 erg/cm 2 for t Ru = 0.6 nm, the unit 1 Oe = 79.5775 A·m −1 ), which was higher than the previous studies.

Temperature Dependence of the Magnetic Properties of IrMn/CoFeB/Ru/CoFeB Exchange Biased Synthetic Antiferromagnets

“…Noteworthy, J eff was reduced reversibly by 60-65% from room temperature to 250 • C with only slight variations across different sets, suggesting that even mild heating treatment could significantly and temporarily alter the SAF coupling strength, with high potential for applications. These results were consistent with those found in similar system, namely synthetic antiferromagnets based on thin ferromagnetic layers with in plane and perpendicular to the plane magnetic anisotropies [35,42]. The theoretical explanation of the decrease of interlayer exchange coupling with the temperature can be found in [41].…”

Ultralow Current Switching of Synthetic‐Antiferromagnetic Magnetic Tunnel Junctions Via Electric‐Field Assisted by Spin–Orbit Torque

“…However, when I SOT ≥ 0.75 mA (J SOT ≥ 4.3 × 10 7 A cm −2 ), |H stray | decreases by approximately 40.0 Oe at both V VCEC = +0.5 and −0.5 V. The nonlinear behavior of H stray with I SOT can be explained by a combination of two factors. One is the effect of Joule heating due to the temperature dependence of IEC in SAF structures [41,42] and the second is the out-of-plane component of the effective field (H SOT Z ) generated by I SOT caused by the competing spin currents from materials with opposite θ SH in the bilayered spin Hall channel. [30] Unlike Joule heating and H SOT IP , H SOT Z is dependent on the sign of I SOT , therefore, we determined that H SOT Z increases by ≈7.0 Oe mA −1 by measuring the difference in H stray at positive and negative I SOT (see Note S4 and Figure S6 in the Supporting Information).…”

Influence of Material Parameters on the Stability of Artificial Skyrmion in Hard/Soft Magnetic Bilayers

“…As shown in Figure 5a, the spin texture of the hard magnetic layer is the Néel‐type skyrmion. The strength of interlayer exchange between two magnetic layers can be tailored by adding spacer layer (nonmagnetic spacing layer such as Ru, Rh, or Ir; antiferromagnetic such as NiO, Cr 2 O 3 , or Cr), [ 31,32 ] or via adjusting the working temperature [ 32 ] and controlling the interface roughness. [ 33 ] Particularly, in Co(3 nm)/Cr/Fe(10 nm) trilayers, the two magnetic layers have been found to decouple at high temperature.…”

“…[ 33 ] Particularly, in Co(3 nm)/Cr/Fe(10 nm) trilayers, the two magnetic layers have been found to decouple at high temperature. [ 32,34 ] The interlayer exchange constant could be tailored from 1 × 10 −11 to 0 J m −1 through adding a spacer layer for different temperature.…”