Effects of perpendicular anisotropy on the interlayer coupling in perpendicularly magnetized [Pd∕Co]∕Cu∕[Co∕Pd] spin valves

Thiyagarajah, Naganivetha; Bae, Seongtae; Joo, Ho Wan; Han, Young Chul; Kim, Jongryoul

doi:10.1063/1.2839596

Cited by 22 publications

(6 citation statements)

References 8 publications

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“…The perpendicular components in orbital moments of each element taken at NI were calculated to be 0.15, 0.01, and 0.005 μ B for Co, Cu, and Pt, respectively. The values in Co and Cu are slightly larger than those reported previously for in-plane Co/Cu multilayers 17 . Although the interfacial Pt layer is spin-polarized by proximity, the polarization decays rapidly in the bulk.…”

Section: Resultscontrasting

confidence: 70%

“…Moreover, the Co/Cu multilayer structures possessing in-plane anisotropy derived from the shape anisotropy in thin films have been investigated extensively because they are utilized for giant magneto-resistance devices12131415. The non-magnetic Cu spacer layers cause behavior similar to Ruderman-Kittel-Kasuya-Yosida (RKKY) oscillatory behavior in the exchange coupling between the magnetic Co layers15161718. Induced magnetism in Cu is also observed through the proximity effect with magnetic atoms1920212223.…”

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confidence: 99%

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Induced perpendicular magnetization in a Cu layer inserted between Co and Pt layers revealed by x-ray magnetic circular dichroism

Okabayashi

Koyama

Suzuki

et al. 2017

Sci Rep

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We used x-ray absorption spectroscopy and x-ray magnetic circular dichroism to investigate the effects of inserting Cu into Co/Pt interfaces, and found that a 0.4-nm-thick inserted Cu layer showed perpendicularly magnetized properties induced by the proximity effect through the Co and Pt layers. The dependence of the magnetic properties on the thickness of the Cu layers showed that the proximity effects between Co and Pt with perpendicular magnetic anisotropy can be prevented by the insertion of a Cu layer with a nominal threshold thickness of 0.7 nm. Element-specific magnetization curves were also obtained, demonstrating that the out-of-plane magnetization is induced in the Cu layers of the Co/Cu/Pt structures.

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Section: Resultscontrasting

confidence: 70%

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confidence: 99%

Induced perpendicular magnetization in a Cu layer inserted between Co and Pt layers revealed by x-ray magnetic circular dichroism

Okabayashi

Koyama

Suzuki

et al. 2017

Sci Rep

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“…The value of H c was reported to be 1300 Oe for the multilayer [Co(0.3)/Pd(1)] 14 21) and it was in the range from 500 to 1000 Oe for the multilayer [Co(0.3)/Pd(0.6)] 4 . 22) However, with the presence of the CoFeB layer, the present CoFeB/Pd multilayers should be more suitable for MgO-based pMTJs with high TMR values, an essential component for a STT MRAM with a low critical current density.…”

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confidence: 96%

Strong Perpendicular Magnetic Anisotropy in CoFeB/Pd Multilayers

Jung

Jeong

Lim

et al. 2010

Appl. Phys. Express

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The strong perpendicular magnetic anisotropy (PMA), indicated by a large coercivity of 590 Oe, is obtained in CoFeB/Pd multilayers through a systematic study that involves using various substrates (Si, glass, sapphire, and MgO) and seed layers (Al and Ta) and also varying the thickness of the seed layer. The PMA is nearly independent of the substrate when Al is used as a seed layer, but the dependence increases significantly with increasing seed layer thickness. The behavior becomes rather complicated for the multilayers with a Ta seed layer, showing a large substrate dependence and a large seed layer thickness dependence.

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“…The spins in the ͓Pd/ Co͔ 5 multilayers almost lie in the perpendicular direction making precession around an angle of 5°f rom the perpendicular direction. 31 After annealing at 240°C with a strong magnetic field applied along the perpendicular direction, the spins in the ͓Pd/ Co͔ 5 multilayers are realigned such that they precess about the perpendicular direction, since the perpendicular K FM,eff is increased. The perpendicular anisotropy K FM,eff , which is proportional to the anisotropy field H k , defined as the intersection point of the hard and easy M-H loops, 32 is approximately estimated to increase by 50%, and 80% after the perpendicular magnetic annealing at 1.2 kOe and 3.3 kOe, respectively.…”

Section: Figmentioning

confidence: 99%

A physical model of exchange bias in [Pd/Co]5/FeMn thin films with perpendicular anisotropy

Lin¹,

Thiyagarajah²,

Joo³

et al. 2010

Journal of Applied Physics

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A physical model of perpendicular exchange bias (PEB) has been established based on the total energy equation per unit area of an exchange bias system by assuming coherent rotation of the magnetization. The anisotropy energy of antiferromagnetic (AFM) layer, KAFM×tAFM, as well as ferromagnetic (FM) multilayers, KFM,eff×tFM, and the interfacial exchange coupling energy, Jex were considered as primary physical parameters in building up the physical model of PEB phenomenon. It was proposed that the PEB is a result of the energy competition between KAFM×tAFM, KFM,eff×tFM, and Jex; where KAFM×tAFM≥Jex, is a critical condition to observe exchange bias in the system. In particular, it was revealed that Jex is directly relevant to the net magnetization of FM and AFM spin structure, Jex∝cos αAFM×cos βFM, in the perpendicular direction rather than the magnetization angle difference observed in an in-plane system. The physical role of perpendicular anisotropy energy, KFM,eff×tFM was also found to be significant to enhance the PEB. These physical characteristics are completely different from those are observed from an exchange bias system with in-plane anisotropy. The physical validity of the proposed PEB model was confirmed using different structures of exchange biased [Pd/Co]5/FeMn thin films with perpendicular anisotropy. The experimentally analyzed results demonstrated that the physical model of PEB proposed in this work is agreed well with the experimentally observed PEB phenomenon. Furthermore, the proposed model was found to be effective to design and to predict a new PEB system for the advanced spintronics applications.

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Effects of perpendicular anisotropy on the interlayer coupling in perpendicularly magnetized [Pd∕Co]∕Cu∕[Co∕Pd] spin valves

Cited by 22 publications

References 8 publications

Induced perpendicular magnetization in a Cu layer inserted between Co and Pt layers revealed by x-ray magnetic circular dichroism

Induced perpendicular magnetization in a Cu layer inserted between Co and Pt layers revealed by x-ray magnetic circular dichroism

Strong Perpendicular Magnetic Anisotropy in CoFeB/Pd Multilayers

A physical model of exchange bias in [Pd/Co]5/FeMn thin films with perpendicular anisotropy

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