Giant magnetoresistance in perpendicularly magnetized synthetic antiferromagnetic coupling with Ir spacer

• Published in: AIP advances Vol. 8; no. 5; pp. 055925 - 055925-6
• Main Authors: Fukushima, A., Taniguchi, T., Sugihara, A., Yakushiji, K., Kubota, H., Yuasa, S.
• Format: Journal Article
• Language: English
• Published: Melville American Institute of Physics 01.05.2018; AIP Publishing LLC
• Subjects: Antiferromagnetism; Coupling; Giant magnetoresistance; Hard disks; Interlayers; Iridium; Magnetic fields; Magnetoresistance; Magnetoresistivity; Random access memory; Tunnel junctions
• ISSN: 2158-3226; 2158-3226
• DOI: 10.1063/1.5007304

Perpendicularly magnetized magnetic tunnel junction (p-MTJ) is a key element for developing high-density spin-transfer torque switching magnetoresistive random access memory. Recently, a large exchange coupling (IEC) in the synthetic antiferromagnetic reference layer with Ir interlayer was observed in p-MTJs. The evaluation of the IEC is, however, difficult due to the electrostatic breakdown of MTJs. This study demonstrates the evaluation of the IEC with Ir interlayer in giant magnetoresistive (GMR) nanopillar. We fabricated three kinds of perpendicularly magnetized GMR elements; bottom-free structures with Cu or Ir spacer, and top-free structure with Ir spacer. The magnetoresistance (RH) loops of all samples show sharp changes of the magnetoresistance at the magnetic fields over ±10 kOe, indicating the existence of the large IECs. In particular, a sharp change of the magnetoresistance at the field over ±20 kOe was found for the element with Cu of 2 nm thickness.