NiFe/CoFeB spin-valve heads for over 5 Gbit/in/sup 2/ density recording

Kanai, H.; Kane, J.; Yamada, Kazuhiko; Aoshima, Ken-ichi; Kanamine, M.; Toda, J.; Mizoshita, Y.

doi:10.1109/20.617782

Cited by 23 publications

(5 citation statements)

References 6 publications

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“…With this achievement, to obtain a recording density of 40-100 Gbit/in 2 using magnetic media is not just a dream in the near future. Significant progresses have also been made in the new generation of read head by using various types of GMR (giant magnetoresistive) spin valve multilayers [3][4][5][6] that fulfill the challenging requirements of reading process at high speed/frequency on high recording density media.…”

Section: Introductionmentioning

confidence: 99%

Structural and electrical properties of tantalum nitride thin films fabricated by using reactive radio-frequency magnetron sputtering

et al. 2001

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Ta-N thin film is an attractive interlayer as well as a diffusion barrier layer in [Fe-N/Ta-N] n multilayers for the application as potential write head materials in high density magnetic recording. We synthesized two series of Ta-N films on glass and Si substrates by using reactive radio frequency sputtering under 5 mtorr Ar/N 2 processing pressure with varied N 2 partial pressure, and carried out systematical characterization analyses of the films. We observed clear changes of phases in the films from metallic bcc Ta to a mixture of bcc Ta(N) and hexagonal Ta 2 N, then sequentially to fcc TaN and a mixture of TaN with N-rich phases when N 2 partial pressure increased from 0.0% to 30%. The changes were associated with changes in the grain shapes as well as in the preferred crystalline orientation of the films from bcc Ta [100] to [110], then to random and finally to fcc TaN [111], correspondingly. It was also associated with a change in film resistivity from metallic to semiconductor-like behavior in the range of 77K-295K. The films showed typical polycrystalline textured structure with small, crystallized domains and irregular grain shapes. Clear preferred (111) stacks parallel to the substrate surface with embedded amorphous regions were observed in the film. TaN film with [111] preferred orientation and a resistivity of 6.0 mΩ•cm was obtained at 25% N 2 partial pressure, which may be suitable for the interlayer in [Fe-N/Ta-N] n multilayers.

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Section: Introductionmentioning

confidence: 99%

Structural and electrical properties of tantalum nitride thin films fabricated by using reactive radio-frequency magnetron sputtering

et al. 2001

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“…A small amount of B is added to Co 90 Fe 10 to improve the thermal stability. 14 We deposited the first two capping layers, Ta and Cu/Ta, by rf sputtering using Ar. We used a plasma oxidation method for the Cu/Al 2 O 3 capping.…”

Section: Methodsmentioning

confidence: 99%

Interlayer exchange coupling in spin valves with specularly reflective oxide layers

Hong

Kanai

2003

Journal of Applied Physics

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We found that capping a spin valve with thin oxide can make the interlayer coupling oscillatory as a function of thickness of the Cu spacer. The coupling was antiferromagnetic and it allowed us to reduce the thickness of the Cu spacer down to 20 Å without sacrificing the good properties of the spin valve. In addition, the oxide layer enhanced specular reflection of conduction electrons at the interface. As a result, we could greatly increase the giant magnetoresistance (GMR) value of the spin valve. The fact that less current shunted through the thinned Cu spacer and the enhancement of specular reflection contributed to the large GMR value. We also report the observation of the oscillation of interlayer coupling as a function of thickness of the magnetic layer in a spin valve.

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“…Perpendicular magnetic anisotropy (PMA) in trilayers of nonmagnetic metal/ferromagnet/heavy metal (NM/FM/HM) or insulator/ferromagnet/heavy metal (I/FM/HM) is of great interest for spintronic applications such as spin-transfer-torque random access memory (STT-RAM), 1,2 magnetoelectric RAM, 3,4 and spin valves. [5][6][7][8][9] These perpendicularly magnetized heterostructures, where the NM and I layers are usually Cu and MgO, respectively, and the HM layer (Ru, Pd, Hf, Ta, Pt, Au) has strong spin orbit coupling (SOC), promise lower critical current for magnetization switching, faster magnetic switching, smaller magnetic bits, and high thermal stability. 1,9,10 Recently, it was shown that the material type and thickness of the HM layer play crucial role not only on the MA [11][12][13][14][15][16][17] but also on the voltage control 18 and magneto-transport behavior 7,14,16,19,20 of these trilayers.…”

Section: Introductionmentioning

confidence: 99%

Oscillatory magnetic anisotropy and spin-reorientation induced by heavy-metal cap in Cu/FeCo/ M ( M=Hf or Ta): A first-principles study

et al. 2016

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Using ab initio electronic structure calculations we have investigated the effect of thickness of heavy metal (HM) cap on the magnetic anisotropy of the Cu/FeCo/HM(n) thin film, where HM=Hf and Ta with thickness n=0-10 monolayers (MLs). We find that the Hf cap results in a large perpendicular magnetic anisotropy (PMA), which exhibits quasi-periodic oscillation with a period of 2-MLs. In contrast, the Ta-capped heterostructure exhibits a spin reorientation from out-of to inplane magnetization orientation at 2-MLs of Ta. Moreover, the MA remains negative and depends weakly on Ta cap thickness beyond the critical thickness. The underlying mechanism of the PMA oscillation is the periodic change of spin-flip spin-orbit coupling (SOC) between the minority-spin Fe d(xz, yz) and majority Fe d(z 2) at Γ, which is induced by the hybridization with Hf at the FeCo/Hf interface. Our results help resolve the contradictory experiments regarding the role of the FeCo/Ta interface on the PMA of the MgO/FeCo/Ta junction. The calculations reveal that the ferromagnet/Hf is promising for spintronic applications and that the capping material and thickness are additional parameters for optimizing the functional properties of spintronic devices.

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NiFe/CoFeB spin-valve heads for over 5 Gbit/in/sup 2/ density recording

Cited by 23 publications

References 6 publications

Structural and electrical properties of tantalum nitride thin films fabricated by using reactive radio-frequency magnetron sputtering

Structural and electrical properties of tantalum nitride thin films fabricated by using reactive radio-frequency magnetron sputtering

Interlayer exchange coupling in spin valves with specularly reflective oxide layers

Oscillatory magnetic anisotropy and spin-reorientation induced by heavy-metal cap in Cu/FeCo/ M ( M=Hf or Ta): A first-principles study

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