Enhancement of magnetoresistance by hydrogen ion treatment for current-perpendicular-to-plane giant magnetoresistive films with a current-confined-path nano-oxide layer

Yuasa, Hiromi; Hara, Michiko; Murakami, Shuichi; Fuji, Yoshihiko; Fukuzawa, H.; Zhang, K.; Li, M.; Schreck, Erhard; Wang, P.; Chen, M.

doi:10.1063/1.3486117

Cited by 11 publications

(4 citation statements)

References 18 publications

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“…In 2010, Yuasa et al [270] of Toshiba reported NOL-based MR ratios ranging from 25% to 27.4%, coupled with ARs ranging from 400 to 4000 fΩm 2 , after using a hydrogen ion treatment (HIT) on a FeCobased EBSV CCP multilayer. To form the NOL, they started with a thin AlCu layer, which they first subjected to IAO to fully oxidize the Al to Al 2 O 3 but leave the Cu less oxidized to give Cu pinholes to form the CCPs.…”

Section: Historymentioning

confidence: 99%

CPP magnetoresistance of magnetic multilayers: A critical review

Bass

2016

Journal of Magnetism and Magnetic Materials

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We present a comprehensive, critical review of data and analysis of Giant (G) Magnetoresistance (MR) with Current-flow Perpendicular-to-the-layer-Planes (CPP-MR) of magnetic multilayers [F/N] n (n = number of repeats) composed of alternating nanoscale layers of ferromagnetic (F) and non-magnetic (N) metal, or of spin-valves that allow control of anti-parallel (AP) and parallel (P) orientations of the magnetic moments of adjacent F-layers. GMR, a large change in resistance when an applied magnetic field changes the moment ordering of adjacent F-layers from AP to P, was discovered in 1988 in the geometry with Current flow in the layer-Planes (CIP). The CPP-MR has two advantages over the CIP-MR: (1) relatively simple two-current series-resistor (2CSR) and more general Valet-Fert (VF) models allow more direct access to the underlying physics; and (2) it is usually larger, which should be advantageous for devices. When the first CPP-MR data were published in 1991, it was not clear whether electronic transport in GMR multilayers is completely diffusive or at least partly ballistic. It was not known whether the properties of layers and interfaces would vary with layer thickness or number. It was not known whether the CPP-MR would be dominated by scattering within the F-metals or at the F/N interfaces. Nothing was known about: (1) spin-flipping within F-metals, characterized by a spin-diffusion length, ; (2) interface specific resistances (AR = area A times resistance R) for N1/N2 interfaces; (3) interface specific resistances and interface spin-dependent scattering asymmetry at F/N and F1/F2 interfaces; and (4) spin-flipping at F/N, F1/F2 and N1/N2 interfaces. Knowledge of spin-dependent scattering asymmetries in F-metals and F-alloys, and of spin-flipping in N-metals and N-alloys, was limited. Since 1991, CPP-MR measurements have quantified the scattering and spin-flipping parameters that determine GMR for a wide range of F-and N-metals and alloys and of F/N pairs. This review is designed to provide a history of how knowledge of CPP-MR parameters grew, to give credit for discoveries, to explain how combining theory and experiment has enabled extraction of quantitative information about these parameters, but also to make clear that progress was not always direct and to point out where disageements still exist. To limit its length, the review considers only collinear orientations of the moments of adjacent F-layers. To aid readers looking for specific information, we have provided an extensive table of contents and a detailed summary. Together, these should help locate over 100 figures plus 17 tables that collect values of individual parameters. In 1997, CIP-MR replaced anisotropic MR (AMR) as the sensor in read heads of computer hard drives. In principle, the usually larger CPP-MR was a contender for the next generation read head sensor. But in 2003, CIP-MR was replaced by the even larger Tunneling MR (TMR), which has remained the read-head sensor ever since. However, as memory bits shrink to where the relative...

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Section: Historymentioning

confidence: 99%

CPP magnetoresistance of magnetic multilayers: A critical review

Bass

2016

Journal of Magnetism and Magnetic Materials

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“…Figure 19 [106] compares calculated values of signal-to-noise ratios (SNR) for such a CCP device, with TMR and all metallic CPP-MR devices with plausible assumed values of AR and MR%. Hydrogen ion treatment (HIT) increased the CPP-MR of a CCP-based multilayer to about 25 % for AR $ 500 fOm 2 [114]. To be competitive for devices, both the size and distribution of channels would have to be well controlled in nm-scale pillars, control not yet demonstrated.…”

Section: Current-confined Paths (Ccp) Via Nano-oxide Layers (Nol)mentioning

confidence: 99%

CPP-GMR: Materials and Properties

Bass¹

2014

Handbook of Spintronics

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“…It has been reported that a current-confined-path (CCP) structure is useful for improving CPP-GMR. [9][10][11][12] The structure is made of a thin insulator with metallic nano-holes that confine current paths in real space. To attain higher MR ratio, however, CPP-GMR must be further improved.…”

Section: Introductionmentioning

confidence: 99%

First-principles study of quantum-transport properties of Fe/Fe₂VAl/Fe trilayers: Design for confined k-space current-perpendicular-to-plane giant-magnetoresistance

Yabuuchi

Kitagawa

2014

Jpn. J. Appl. Phys.

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The electronic structure and quantum-transport properties of Fe/Fe2VAl/Fe trilayers were investigated by using first-principles calculations. The high-transmission area in k-space can be confined by using a semimetallic Fe2VAl layer. The confined k-space originates from the small Fermi surface of Fe2VAl. Moreover, the symmetry matching of wave functions between the leads and space of the trilayer around the Fermi level is a significant factor in regard to designing confined-k-space current-perpendicular-to-plane giant-magnetoresistance (CPP-GMR) device, which is a promising candidate to provide a resistance area (RA) product that is difficult to achieve by using conventional insulators and metals.

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Enhancement of magnetoresistance by hydrogen ion treatment for current-perpendicular-to-plane giant magnetoresistive films with a current-confined-path nano-oxide layer

Cited by 11 publications

References 18 publications

CPP magnetoresistance of magnetic multilayers: A critical review

CPP magnetoresistance of magnetic multilayers: A critical review

CPP-GMR: Materials and Properties

First-principles study of quantum-transport properties of Fe/Fe₂VAl/Fe trilayers: Design for confined k-space current-perpendicular-to-plane giant-magnetoresistance

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Enhancement of magnetoresistance by hydrogen ion treatment for current-perpendicular-to-plane giant magnetoresistive films with a current-confined-path nano-oxide layer

Cited by 11 publications

References 18 publications

CPP magnetoresistance of magnetic multilayers: A critical review

CPP magnetoresistance of magnetic multilayers: A critical review

CPP-GMR: Materials and Properties

First-principles study of quantum-transport properties of Fe/Fe2VAl/Fe trilayers: Design for confined k-space current-perpendicular-to-plane giant-magnetoresistance

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First-principles study of quantum-transport properties of Fe/Fe₂VAl/Fe trilayers: Design for confined k-space current-perpendicular-to-plane giant-magnetoresistance