Study of Magnetization Reversal Process in FeCo/Ru/FeCo Exchange Coupled Synthetic Antiferromagnetic Multilayers

Abstract

FeCo/Ru/FeCo exchange coupled synthetic antiferromagnetic multilayers were prepared with two sputtering modes. One is continuous sputtering mode, and the other mode is layer-by-layer sputtering mode. The former mode implies that substrate faced the target and film growth process was continuous when FeCo layers were sputtering, whereas the latter implies that substrate was rotating with the mask at a speed of 5 rpm when FeCo layers were sputtering. It was found that the exchange coupling fieldHexof sample sputtered by layer-by-layer mode was higher than the one sputtered by continuous mode. Domain structures were measured with applying varied in-plane magnetic fields along the easy axis in order to study the magnetization reversal process. We found it is a domain wall move process. When the applied field is smaller thanHex, both the two magnetic layers have domain structure and the domain structure of the two layers is reversed correspondingly. When the applied field is varying in the range of-HextoHex, the domain wall of the two layers moves correspondingly at the same time.

Ionic liquid gating control of RKKY interaction in FeCoB/Ru/FeCoB and (Pt/Co)2/Ru/(Co/Pt)2 multilayers

“…Nevertheless, since the alternative spins at the AFM/FM interface are strongly pinned by AFM layer, these E-field control processes are usually confined at a low temperature 20 , 21 or require an H-field assistance 22 . To overcome these difficulties, we considered the synthetic antiferromagnetic (SAF) multilayer as an easier way to manipulate AFM coupling 5 , 23 , 24 . In the SAF structure, two FM layers separated by a nonmagnetic (NM) metallic spacer layer have indirect interaction through interlayer exchange coupling (IEC) 24 .…”

“…To overcome these difficulties, we considered the synthetic antiferromagnetic (SAF) multilayer as an easier way to manipulate AFM coupling 5 , 23 , 24 . In the SAF structure, two FM layers separated by a nonmagnetic (NM) metallic spacer layer have indirect interaction through interlayer exchange coupling (IEC) 24 . According to the Ruderman–Kittel–Kasuya–Yosida (RKKY) interaction theory 24 – 27 , whether the FM layers are ferromagnetically or antiferromagnetically coupled is determined by the thicknesses of NM layer 25 .…”

“…In the SAF structure, two FM layers separated by a nonmagnetic (NM) metallic spacer layer have indirect interaction through interlayer exchange coupling (IEC) 24 . According to the Ruderman–Kittel–Kasuya–Yosida (RKKY) interaction theory 24 – 27 , whether the FM layers are ferromagnetically or antiferromagnetically coupled is determined by the thicknesses of NM layer 25 . Many researches regarding SAF heterostructures have been done 26 – 31 .…”

Marked Enhancement of Roll-Off Frequency in FeCoN Synthetic Antiferromagnetic Films Deposited by Oblique Incidence

“…To introduce exchange anisotropy, the FeCoN SAF structure films are prepared. In the SAF structure, two ferromagnetic (FM) layers separated by a nonmagnetic (NM) metallic spacer layer have a Ruderman–Kittel–Kasuya–Yosida (RKKY) interaction which is indirect interaction through interlayer exchange coupling [23]. Depending on the thickness, the NM layer can mediate either a ferromagnetic or antiferromagnetic exchange coupling between two FM layers [24].…”