Abstract

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.

Highlights

  • As is widely claimed by several studies, current-perpendicular-to-the-plane giant magnetoresistance (CPP-GMR) devices have been promising candidates as the magnetic read sensors for ultrahigh areal densities (ADs) of magnetic data storage technology [1–6].In the past few decades, the outstanding features of the CPP-GMR reader, i.e., large magnetoresistive (MR) outputs, extremely low resistance area (RA) product, capability of transferring large amounts of data at high speeds, and low thermal fluctuation, have been extensively proved [2,7–9]

  • The properties of Co2 (Mn0.6 Fe0.4 )Ge (CMFG) Heusler alloy aretypically adopted from reference [15], It ismagnetic well known that a few nanometers of thickness layers have an influential impactsaturation on the readmagnetization head performance, at higher

  • The output characteristics of the CPP‐GMR read head were chara ized at different tFL from 1 to 10 nm

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Summary

Introduction

As is widely claimed by several studies, current-perpendicular-to-the-plane giant magnetoresistance (CPP-GMR) devices have been promising candidates as the magnetic read sensors for ultrahigh areal densities (ADs) of magnetic data storage technology [1–6]. The CPP-GMR sensors based on ferromagnetic Heusler alloys are the most capable integrations that can provide very high performance of CPP-GMR sensors nowadays [14–19]. Several studies have attempted to improve the MR output of the CPP-GMR sensors using various Heusler alloy compositions; recent studies indicate that using the Co2 (Mn0.6 Fe0.4 )Ge (CMFG). The reader shield-to-shield spacing (SSS) is one of the structural parameters directly related to the physical dimension of the head. It has a major impact on the down-track resolution. The thickness of reader layers is a relative sizing parameter of the SSS. We studied the dependence of the free layer thickness of the CPP-GMR reader on the head’s stability performance.

CPP-GMR Modelling
Analysis of Read Head Response
Analysis
Results and Discussion
Conclusions
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