Perspectives on spintronics technology development: Giant magnetoresistance to spin transfer torque magnetic random access memory

M Pinarbasi,A D Kent

doi:10.1063/5.0075945

Abstract

The discovery of the giant magnetoresistance (GMR) effect in 1988 started a new field called spintronics and was recognized with the 2007 Nobel Prize in Physics, which was awarded to Fert and Grunberg. Spintronics is based on the contribution of both electron spin and electron charges of materials to facilitate electronic functions, enabling one extra degree of freedom for device operations. Spintronics has grown rapidly during the past three decades with significant discoveries, technological advancements, and material and device developments that have led to numerous product applications. Furthermore, new research fields and technology areas have been discovered and continue to expand. In this Perspective, key technological advances in the field during the past three decades will be highlighted, starting with the developments that led to the first use of the GMR effect in hard disk drives and its impact in the spintronic ecosystem to currently used perpendicular magnetic tunnel junctions (pMTJs) for spin transfer torque magnetic random access memory (STT-MRAM) devices. The important aspects of the pMTJ characteristics for the application of STT-MRAM will be discussed. This Perspective will present perspectives on a new structure that enhances the efficiency of the pMTJ-based STT-MRAM and research directions that can drive further advances in spintronics.

Highlights

Discoveries in magnetism and magnetic materials have driven enormous advances in information storage technology and digital information storage density.1–8 The corollary is true: advances in industry have enabled more sophisticated devices and material structures that challenge our understanding of the underlying physics
As magnetoresistive effects [the relatively small anisotropic magnetoresistance (AMR)11] were already being used to read magnetic information on hard disk drives (HDDs),2 it was quickly recognized that giant magnetoresistance (GMR) structures could significantly enhance the read signal and, HDD memory capacity
Work during the development of the GMR technology for HDD application started with magnetic materials, processing, magnetic multilayers, deposition tooling, and device applications and, initiated the formation of the ecosystem that we use today for magnetic random access memory (MRAM) technology

Summary

Introduction

Discoveries in magnetism and magnetic materials have driven enormous advances in information storage technology and digital information storage density. The corollary is true: advances in industry have enabled more sophisticated devices and material structures that challenge our understanding of the underlying physics. The corollary is true: advances in industry have enabled more sophisticated devices and material structures that challenge our understanding of the underlying physics In this Perspective, we highlight this productive interplay between magnetism research and its applications and provide our views on present research developments that can have a technological impact. As magnetoresistive effects [the relatively small anisotropic magnetoresistance (AMR)11] were already being used to read magnetic information on hard disk drives (HDDs), it was quickly recognized that GMR structures could significantly enhance the read signal and, HDD memory capacity. This discovery, started a worldwide effort to develop the technology of highly sensitive GMR read sensors for HDD applications. After the discovery of GMR, research and development in the spintronic field was largely carried out by HDD magnetic head industry

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