Unstable Playback Response of CPP-GMR Read Head Induced by Electromagnetic Interference: Structural Dependence

Khunkitti, Pirat; Kruesubthaworn, Anan; Kaewrawang, Arkom

doi:10.1109/tmag.2019.2935419

Cited by 4 publications

(5 citation statements)

References 26 publications

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“…As shown in Figure 1 a, the sensing layers of the CPP-GMR read head targeted for AD of 1 Tb/in 2 are modelled, assuming that the head is sensing the magnetic stray field, H stray , of the medium. The reader width and stripe height of the head were set at 60 and 48 nm, respectively, since this dimension was claimed as the appropriate value for the CPP-GMR reader at an AD of 1 Tb/in 2 [ 30 ]. The combination of the CMFG electrodes and AgSn/InZnO spacer was performed due to their suitability for practical CPP-GMR devices [ 15 ].…”

Section: Cpp-gmr Modellingmentioning

confidence: 99%

Free Layer Thickness Dependence of the Stability in Co2(Mn0.6Fe0.4)Ge Heusler Based CPP-GMR Read Sensor for Areal Density of 1 Tb/in2

Khunkitti

Siritaratiwat

Pituso³

2021

Micromachines

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Current-perpendicular-to-the-plane giant magnetoresistance (CPP-GMR) read sensors based on Heusler alloys are promising candidates for ultrahigh areal densities of magnetic data storage technology. In particular, the thickness of reader structures is one of the key factors for the development of practical CPP-GMR sensors. In this research, we studied the dependence of the free layer thickness on the stability of the Co2(Mn0.6Fe0.4)Ge Heusler-based CPP-GMR read head for an areal density of 1 Tb/in2, aiming to determine the appropriate layer thickness. The evaluations were done through simulations based on micromagnetic modelling. The reader stability indicators, including the magnetoresistance (MR) ratio, readback signal, dibit response asymmetry parameter, and power spectral density profile, were characterized and discussed. Our analysis demonstrates that the reader with a free layer thickness of 3 nm indicates the best stability performance for this particular head. A reasonably large MR ratio of 26% was obtained by the reader having this suitable layer thickness. The findings can be utilized to improve the design of the CPP-GMR reader for use in ultrahigh magnetic recording densities.

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Section: Cpp-gmr Modellingmentioning

confidence: 99%

Free Layer Thickness Dependence of the Stability in Co2(Mn0.6Fe0.4)Ge Heusler Based CPP-GMR Read Sensor for Areal Density of 1 Tb/in2

Khunkitti

Siritaratiwat

Pituso³

2021

Micromachines

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“…The aj = (Jħg())/(2eMs) is a spin torque factor where J is the polarized current density, ħ is the reduced Planck's constant, e is the electron charge value and  is the free layer thickness. The scalar function is given as g() = [-4+(1+p) 3 (3+cos)/4p 3/2 ] -1 , where  is the angle between the magnetizations of the free layer and the reference layer. A 2.5 × 2.5 × 2.5 nm 3 computational cell size and 0.1 ps time step were set for all cases of the simulations.…”

Section: A Modelling Of the Cpp-gmr Read Sensorsmentioning

confidence: 99%

“…On the other hand, an important finding was that the readback signal became more symmetric and less distorted at shorter SH and longer RW lengths. Higher distortion of signal from the head with longer SH and shorter RW lengths can be physically explained by the behavior of the demagnetization field, Hdemag, over the free layer region [3]. The Hdemag is theoretically a force pulling the magnetization toward the its opposite direction, which results in fluctuating magnetization dynamic causing higher instabilities.…”

Section: A Optimal Sizing Ot the Cpp-gmr Sensor For Ad Of 1 Tb/inmentioning

confidence: 99%

“…As the areal density (AD) of the hard disk drive (HDD) is expected to reach 10 Tb/in 2 in the coming decade, challenges in developing the magnetic recording heads to deal with a shrinking of media bit size have been extensively researched [1][2][3]. The current-perpendicular-to-the-plane giant magnetoresistance (CPP-GMR) sensors have been promising candidates to overcome the limitations to reach ultrahigh storage capacities, due mainly to their extremely small resistance-area and their high rate of data transfer [4][5][6].…”

Section: Introductionmentioning

confidence: 99%

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Optimal Sizing of CPP-GMR Read Sensors for Magnetic Recording Densities of 1–4 Tb/in²

Khunkitti

Pituso²,

Chaiduangsri³

et al. 2021

IEEE Access

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Several studies have confirmed that current-perpendicular-to-the-plane giant magnetoresistance (CPP-GMR) technology is appropriate for next-generation read sensors for ultrahigh areal densities (ADs) of data storage applications. Since the physical dimension of the read sensor is a crucial factor for developing the reader to overcome its limitations, this paper proposes an optimal sizing prediction of the CPP-GMR read heads for ADs of 1-4 Tb/in 2 . Micromagnetic modelling was performed in the simulations. The appropriate length of the stripe height (SH) and the read width (RW) of the readers was estimated based on a consideration of sensor outputs including the readback signal, asymmetry parameter, dibit response and power spectral density (PSD) profile. It was found that a variation of SH and RW lengths had an influential impact on the readback signal waveform. Those affectations were further characterized through the echoes of dibit response showing that shortening the SH length or increasing the RW length could improve the resolution and reduce the distortion occurring in the readback signal. Moreover, the PSD profile indicated that the reader operation became more stable at shorter SH lengths or longer RW lengths. The head response spectrum was also examined. In addition, the magnitude of the bias current was studied in relation to the head response. Lastly, the optimal physical dimension (SH×RW) of the CPP-GMR readers for ADs of 1-4 Tb/in 2 was predicted to be (40×48) nm, (28×29) nm, (25×26) nm and (19×20) nm, respectively. The results can be utilized to design the CPP-GMR sensors at ultrahigh magnetic recording capacities.INDEX TERMS Magnetic recording, Magnetic read heads, Current perpendicular-to-the-plane giant magnetoresistance, Heusler alloys.

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“…The GMR effect was first observed in Fe/Cr multilayer structures by Fert et al and Grünberg et al in 1988 and soon became a popular research topic due to its great potential in the field of hard drives, memories, sensors, etc. [ 16 , 17 , 18 , 19 ]. In 1998, Baselt et al firstly reported the GMR-based biosensors [ 20 ].…”

Section: Introductionmentioning

confidence: 99%

Giant Magnetoresistance Biosensors for Food Safety Applications

Liang

Sutham

et al. 2022

Sensors

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Nowadays, the increasing number of foodborne disease outbreaks around the globe has aroused the wide attention of the food industry and regulators. During food production, processing, storage, and transportation, microorganisms may grow and secrete toxins as well as other harmful substances. These kinds of food contamination from microbiological and chemical sources can seriously endanger human health. The traditional detection methods such as cell culture and colony counting cannot meet the requirements of rapid detection due to some intrinsic shortcomings, such as being time-consuming, laborious, and requiring expensive instrumentation or a central laboratory. In the past decade, efforts have been made to develop rapid, sensitive, and easy-to-use detection platforms for on-site food safety regulation. Herein, we review one type of promising biosensing platform that may revolutionize the current food surveillance approaches, the giant magnetoresistance (GMR) biosensors. Benefiting from the advances of nanotechnology, hundreds to thousands of GMR biosensors can be integrated into a fingernail-sized area, allowing the higher throughput screening of food samples at a lower cost. In addition, combined with on-chip microfluidic channels and filtration function, this type of GMR biosensing system can be fully automatic, and less operator training is required. Furthermore, the compact-sized GMR biosensor platforms could be further extended to related food contamination and the field screening of other pathogen targets.

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Unstable Playback Response of CPP-GMR Read Head Induced by Electromagnetic Interference: Structural Dependence

Cited by 4 publications

References 26 publications

Free Layer Thickness Dependence of the Stability in Co2(Mn0.6Fe0.4)Ge Heusler Based CPP-GMR Read Sensor for Areal Density of 1 Tb/in2

Free Layer Thickness Dependence of the Stability in Co2(Mn0.6Fe0.4)Ge Heusler Based CPP-GMR Read Sensor for Areal Density of 1 Tb/in2

Optimal Sizing of CPP-GMR Read Sensors for Magnetic Recording Densities of 1–4 Tb/in²

Giant Magnetoresistance Biosensors for Food Safety Applications

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