Domain walls and magnetic properties of very thin permalloy films for magnetoresistive sensors

Akhter, M.A.; Mapps, D.J.; Tan, Yang; Petford‐Long, Amanda K.; Doole, R. C.

doi:10.1109/20.706422

Cited by 12 publications

(5 citation statements)

References 2 publications

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“…This is because higher areal density recording requires the use of the AMR sensor layers in the thickness range of strongly diminishing AMR coefficients. For instance, while the AMR coefficient for the bulk permalloy 2 is about 4%, it is р2% for a 150 Å thick film, [3][4][5] which is the thickness required for 1 Gbit/in. 2 recording density.…”

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confidence: 99%

“…2 , the AMR coefficient of permalloy films decreases even faster with film thickness. [3][4][5] Enhancement of the AMR coefficient at low thickness is clearly needed to offset this trend and extend the MR technology to higher areal densities. The AMR coefficient of permalloy can be increased by as much as 50% using high-temperature deposition 4,8 or postannealing.…”

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confidence: 99%

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High magnetoresistance permalloy films deposited on a thin NiFeCr or NiCr underlayer

Lee

Toney

Tameerug

et al. 2000

Journal of Applied Physics

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Significantly enhanced anisotropic magnetoresistance (MR) in permalloy (Ni0.81Fe0.19) films deposited on a thin (Ni0.81Fe0.19)1−xCrx or Ni1−xCrx underlayer is reported. The maximum ΔR/R enhancement was observed using the underlayer with x≈0.44 at an optimum thickness of ≈30–45 Å, depending on the deposition technique. An enhancement of 75%–150% was observed for 45–430 Å thick permalloy films, compared to the films deposited without this underlayer. The ΔR/R enhancement is attributed to the decrease in the resistivity ρ and the increase in Δρ of the permalloy film due to the formation of large (111) textured crystal grains in the permalloy films deposited on this underlayer, as revealed by the x-ray diffraction results obtained using synchrotron radiation.

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confidence: 99%

High magnetoresistance permalloy films deposited on a thin NiFeCr or NiCr underlayer

Lee

Toney

Tameerug

et al. 2000

Journal of Applied Physics

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“…Figure 6͑a͒ illustrates schematically the modeled region within a section of magnetic thin-film. Domain wall density in NiFe thin-films has been observed elsewhere to be dependent upon film thickness and have spacing of the order of a few micrometers, 19 so modeling magnetization switching by the propagation of a single domain wall is a reasonable assumption for modeling on the 10 m scale. Furthermore, the magnetization behavior of the macroscopic thin-film can be represented by the collective behavior of many such single domain walls across the thin-film.…”

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confidence: 99%

Complex pulsed field magnetization behavior and Walker breakdown in a NiFe thin-film

Burn

Atkinson

2010

Journal of Applied Physics

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Use policyThe full-text may be used and/or reproduced, and given to third parties in any format or medium, without prior permission or charge, for personal research or study, educational, or not-for-prot purposes provided that:• a full bibliographic reference is made to the original source • a link is made to the metadata record in DRO • the full-text is not changed in any way The full-text must not be sold in any format or medium without the formal permission of the copyright holders.Please consult the full DRO policy for further details. The magnetization behavior of a Permalloy thin-film ͑nominally Ni 81 Fe 19 ͒ was investigated as a function of combined quasistatic and pulsed magnetic fields measured using magneto-optic Kerr effect magnetometry. We observed complex field dependent switching behavior that depends on the relative contributions to the total field of the quasistatic and pulsed fields. As the pulsed field amplitude was increased, complex switching behavior occurs for total fields in excess of the coercive field. A simple phenomenological domain wall propagation model suggests a qualitative understanding of this complex behavior based on Walker breakdown of the domain wall motion occurring in the Permalloy thin-film.

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“…In order to enlarge the scope of their application, at present, many companies and research groups concerned in the world are tapping the potentialities of AMR reading heads, increasing magnetic field sensitivity, reducing Barkhausen noise, etc. To achieve them, permalloy films used in AMR reading heads must be very thin and they should have as high AMR value and as low coercivity as possible [4,5]. The AMR value of permalloy films can be increased by as much as ∼50% through high-temperature deposition [6] or annealing [7], however, these methods are not suitable for the large-scale production of AMR devices.…”

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confidence: 99%

Ultrathin high anisotropic magnetoresistance Ni_0.81Fe_0.19 films

Li¹,

Yu²,

Teng³

et al. 2006

J. Phys. D: Appl. Phys.

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We have fabricated an ultrathin high anisotropic magnetoresistance (AMR) Ni0.81Fe0.19 (10.0 nm) film grown on a (Ni0.81Fe0.19)0.63Cr0.37 (5.5 nm) underlayer with dc magnetron sputtering. The AMR value (ΔR/R) and the coercivity of the film attain 1.61(6)% and 178 A m−1 (i.e. 2.2 Oe), respectively. The ΔR/R of (Ni0.81Fe0.19)0.63 Cr0.37(5.5 nm)/ Ni0.81Fe0.19(10.0 nm) film has increased by ∼34% over that of Ta(5.4 nm)/Ni0.81Fe0.19(10.0 nm) film (ΔR/R = 1.20(6)%) prepared using the same magnetron sputtering. The results of x-ray diffraction and atomic force microscopy show that the underlayer of (Ni0.81Fe0.19)0.63 Cr0.37 makes it easier to promote the formation of Ni0.81Fe0.19(111) texture and dramatically improves the crystalline grain size in the columnar direction and the average surface grain size of the Ni0.81Fe0.19film. The result of x-ray photoelectron spectroscopy shows that the (Ni0.81Fe0.19)0.63Cr0.37 underlayer, unlike the traditional Ta, does not react with the Ni0.81Fe0.19 film at the interface.

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Domain walls and magnetic properties of very thin permalloy films for magnetoresistive sensors

Cited by 12 publications

References 2 publications

High magnetoresistance permalloy films deposited on a thin NiFeCr or NiCr underlayer

High magnetoresistance permalloy films deposited on a thin NiFeCr or NiCr underlayer

Complex pulsed field magnetization behavior and Walker breakdown in a NiFe thin-film

Ultrathin high anisotropic magnetoresistance Ni_0.81Fe_0.19 films

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Domain walls and magnetic properties of very thin permalloy films for magnetoresistive sensors

Cited by 12 publications

References 2 publications

High magnetoresistance permalloy films deposited on a thin NiFeCr or NiCr underlayer

High magnetoresistance permalloy films deposited on a thin NiFeCr or NiCr underlayer

Complex pulsed field magnetization behavior and Walker breakdown in a NiFe thin-film

Ultrathin high anisotropic magnetoresistance Ni0.81Fe0.19 films

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Ultrathin high anisotropic magnetoresistance Ni_0.81Fe_0.19 films