Study of the interlayer coupling and its temperature dependence in spin valves with Ru and Cu spacers

Abstract

The IrMn/Co/NM/Ni81Fe19 spin valves, with the nonmagnetic (NM) spacers of Ru and Cu, were grown by sputtering and analyzed by magnetization versus magnetic field measurements at several temperatures. The loop of the free layer exhibits a loop shift proportional to the interlayer coupling strength. For fitting the NM layer thickness dependence of this loop shift, the oscillatory interlayer and the magnetostatic Néel mechanisms were considered. These analyses provided quantitative values of both contributions and showed that the oscillatory coupling mechanism dominates in the system with Ru spacer, while the Néel coupling mechanism dominates for the Cu spacer. In both systems, the temperature variations of the coupling are attributed to the spacer and spacer/magnet interfaces.

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

“…It has been found that the H ex and −J iec of SAF multilayers varies significantly with temperature owing to the Fermi surface state of the spacing layer, which has been studied in previous reports. [26,27] Figure 3 shows the normalized out-of-plane M-H loops of the SAF structures with t Ru = 0.6, 0.9 nm at different temperatures, i.e., 100 K, 400 K, and 600 K. As shown in Fig. 3(a), for t Ru = 0.6 nm, the H ex is about 4.8 kOe and the −J iec value was evaluated to be 3.893 erg/cm 2 at 100 K. With temperature increasing, the H ex increased firstly to 5.37 kOe at 400 K, and then decreases to 3.2 kOe at 600 K. However, for t Ru = 0.9 nm, the H ex decreases from 4.4 kOe to 2.1 kOe with temperature increasing from 100 K to 600 K. While, the −J iec decreases from 4.5 erg/cm 2 to 1.53 erg/cm 2 .…”

CoFe2O4 Nanoparticle-Integrated Spin-Valve Thin Films Prepared by Interfacial Self-Assembly

“…Thus, the stray field induced from the magnetic nanoparticles can effectively affect the magnetic orientation of the free layer, and discernible magnetic interactions between the nanoparticles and the free layer can be expected . The first Ru layer was grown as a buffer to promote the (111) texture of IrMn and the last Ru layer serves as a capping to protect the underlying thin films against oxidation . The thickness of the IrMn and CoFe layers were optimized to establish a strong exchange bias effect at the AF/FM interface.…”

“…Spin-valve devices have been widely researched not only due to the fundamental physics of spin transport in their magnetic nanostructures but also the great potential they demonstrate in magnetic recording, storage, and sensing applications. , The standard spin valve consists of two ferromagnetic (FM) layers separated by a nonmagnetic spacer and an antiferromagnetic (AF) layer to pin the magnetization of one FM layer by exchange-bias effect . Early works about spin valves fabricated as giant magnetoresistance (GMR) multilayers mostly focused on the materials and growth of magnetic layers (disordered and ordered AF materials, , crystalline and amorphous FM materials , ), treatment and processing (magnetic annealing, rapid annealing, oxidation , ), and structural modification (current-perpendicular-to-plane geometry, , synthetic antiferromagnets, , dual spin valve, , lateral spin valve , ), leading to the improvement of sensitivity, areal density, magnetoresistance (MR) ratio, exchange-bias field, and so forth.…”

“…1,2 The standard spin valve consists of two ferromagnetic (FM) layers separated by a nonmagnetic spacer and an antiferromagnetic (AF) layer to pin the magnetization of one FM layer by exchange-bias effect. 3 Early works about spin valves fabricated as giant magnetoresistance (GMR) multilayers mostly focused on the materials and growth of magnetic layers (disordered and ordered AF materials, 4,5 crystalline and amorphous FM materials 6,7 ), treatment and processing (magnetic annealing, 8 rapid annealing, 9 oxidation 10,11 ), and structural modification (current-perpendicular-to-plane geometry, 12,13 synthetic antiferromagnets, 14,15 dual spin valve, 13,16 lateral spin valve 17,18 ), 19 leading to the improvement of sensitivity, areal density, magnetoresistance (MR) ratio, exchange-bias field, and so forth. Later on, wide-band gap metal oxides, mainly MgO and Al 2 O 3 , have been used as the tunnel barrier in spin valves and pseudo spin valves deposited as tunneling magnetoresistance (TMR) multilayers, achieving significantly higher MR ratios.…”

Weakly coupled synthetic antiferromagnetic nanodisks with perpendicular magnetic anisotropy for lab-on-chip devices

“…The ion milling step utilises accelerated Ar ions to bombard the film, which has been shown to cause significant modification of magnetic multilayer properties 28 . Firstly, a rise in temperature during milling can disrupt the interfaces through atomic diffusion [29][30][31][32] . Secondly, the bombarding ions can create defects in multiple ways 28,33,34 : Ar ion implantation, sputtering away of stack atoms or mixing of stack atoms.…”