Query:  Roadmap for emerging materials for spintronic device applications

Candidate papers:

abstract: The Technical Committee of the IEEE Magnetics Society has selected seven research topics to develop their roadmaps, where major developments should be listed alongside expected timelines: 1) hard disk drives; 2) magnetic random access memories; 3) domain wall devices; 4) permanent magnets; 5) sensors and actuators; 6) magnetic materials; and 7) organic devices. Among them, magnetic materials for spintronic devices have been surveyed as the first exercise. In this roadmap exercise, we have targeted magnetic tunnel and spin valve junctions as spintronic devices. These can be used, for example, as a cell for a magnetic random access memory and a spin torque oscillator in their vertical form as well as a spin transistor and a spin Hall device in their lateral form. In these devices, the critical role of magnetic materials is to inject spin polarized electrons efficiently into a nonmagnet. We have accordingly identified two key properties to be achieved by developing new magnetic materials for future spintronic devices: 1) half metallicity at room temperature (RT) and 2) perpendicular anisotropy in nanoscale devices at RT. For the first property, five major magnetic materials are selected for their evaluation for future magnetic/spintronic device applications: 1) Heusler alloys; 2) ferrites; 3) rutiles; 4) perovskites; and 5) dilute magnetic semiconductors. These alloys have been reported or predicted to be half metallic ferromagnets at RT. They possess a bandgap at the Fermi level EF only for its minority spins, achieving 100% spin polarization at EF. We have also evaluated L10 alloys and D022 Mn alloys for the development of a perpendicularly anisotropic ferromagnet with large spin polarization. We have listed several key milestones for each material on their functionality improvements, property achievements, device implementations, and interdisciplinary applications within 35 years time scale. The individual analyses and the projections are discussed in the following sections.
author_names: Atsufumi Hirohata

Hiroaki Sukegawa

Hideto Yanagihara

Igor Zutic

Takeshi Seki

Shigemi Mizukami

Rajasekaran Swaminathan
title: Roadmap for Emerging Materials for Spintronic Device Applications
venue: IEEE Transactions on Magnetics
year: 2015

abstract: Spin orbit torque (SOT) is an emerging technology that enables the efficient manipulation of spintronic devices. The initial processes of interest in SOTs involved electric fields, spin orbit coupling, conduction electron spins, and magnetization. More recently, interest has grown to include a variety of other processes that include phonons, magnons, or heat. Over the past decade, many materials have been explored to achieve a larger SOT efficiency. Recently, holistic design to maximize the performance of SOT devices has extended material research from a nonmagnetic layer to a magnetic layer. The rapid development of SOT has spurred a variety of SOT based applications. In this article, we first review the theories of SOTs by introducing the various mechanisms thought to generate or control SOTs, such as the spin Hall effect, the Rashba Edelstein effect, the orbital Hall effect, thermal gradients, magnons, and strain effects. Then, we discuss the materials that enable these effects, including metals, metallic alloys, topological insulators, 2 D materials, and complex oxides. We also discuss the important roles in SOT devices of different types of magnetic layers, such as magnetic insulators, antiferromagnets, and ferrimagnets. Afterward, we discuss device applications utilizing SOTs. We discuss and compare three and two terminal SOT magnetoresistive random access memories (MRAMs) we mention various schemes to eliminate the need for an external field. We provide technological application considerations for SOT MRAM and give perspectives on SOT based neuromorphic devices and circuits. In addition to SOT MRAM, we present SOT based spintronic terahertz generators, nano oscillators, and domain wall and skyrmion racetrack memories. This article aims to achieve a comprehensive review of SOT theory, materials, and applications, guiding future SOT development in both the academic and industrial sectors.
author_names: Qiming Shao

Luqiao Liu

Hyunsoo Yang

Shunsuke Fukami

Armin Razavi

Hao Wu

Kang L Wang

Frank Freimuth

Yuriy Mokrousov

Mark D Stiles

Satoru Emori

Axel Hoffmann

Johan Akerman

Kaushik Roy

Jian-Ping Wang

See-hun Yang

Kevin Garello
title: Roadmap of Spin Orbit Torques
venue: IEEE Transactions on Magnetics
year: 2021

abstract: Part I. Advanced Flash and Nano Floating Gate Memories: 1. Scaling challenges for NAND and replacement memory technology Kirk Prall 2. Growth and in line characterization of silicon nanodots integrated in discrete charge trapping non volatile memories Julien Amouroux 3. Matrix density effect on morphology of germanium nanocrystals embedded in silicon dioxide thin films Arif Alagoz 4. Temperature effects on charge transfer mechanisms of nc ITO embedded ZrHfO high k nonvolatile memory devices Yue Kuo 5. Enhancement of nonvolatile floating gate memory devices containing AgInSbTe SiO2 nanocomposite by inserting HfO2/SiO2 blocking oxide layer Tsung Eong Hsieh Part II. Resistive Switching Memories: 6. Complementary resistive switches (CRS) high speed performance for the application in passive nanocrossbar arrays Roland Rosezin 7. Influence of copper on the switching properties of hafnium oxide based resistive memory Benjamin Briggs 8. Fabrication and characterization of copper oxide resistive memory devices Seann Bishop 9. Influence of process parameters on resistive switching in MOCVD NiO films Dirk Wouters 10. Understanding the role of process parameters on the characteristics of transition metal oxide RRAM/memristor devices Rashmi Jha 11. Memristive switches with two switching polarities in a forming free device structure Rainer Bruchhaus 12. WOx resistive memory elements for scaled flash memories Judit G. Lisoni 13. Memory retention characteristics of data storage area written in transition metal oxide films by using atomic force microscope Kentaro Kinoshita 14. A survey of metal oxides and top electrodes for resistive memory devices Seann Bishop 15. Switching speed in resistive random access memories (RRAMs) based on plastic semiconductor Paulo Rocha 16. Retentivity of RRAM devices based on metal/YBCO interfaces Carlos Acha 17. Electro forming of vacancy doped metal SrTiO3 metal structures Barbara Abendroth Part III. Phase Change, Ferroelectric, and Organic Memories: 18. Interface characterization of metals and metal nitrides to phase change materials Deepu Roy 19. Investigation on phase change behaviors of Si Sb Te alloy: the effect of tellurium segregation Xilin Zhou 20. Recent progress in downsizing FeFETs for Fe NAND application Shigeki Sakai 21. Lanthanum oxide capping layer for solution processed ferroelectric gate thin film transistors Tue Phan 22. New MEH PPV based composite materials for rewritable nonvolatile polymer memory devices Mikhail Dronov 23. Planar non volatile memory based on metal nanoparticles Asal Kiazadeh.
author_names: Dirk J Wouters

Physics for Non-Volatile Memories

Process for Non-Volatile Memories
title: New functional materials and emerging device architectures for nonvolatile memories symposium held April 25 29, 2011, San Francisco, California, U.S.A.
year: 2011

abstract: Author(s) Sander, D; Valenzuela, SO; Makarov, D; Marrows, CH; Fullerton, EE; Fischer, P; McCord, J; Vavassori, P; Mangin, S; Pirro, P; Hillebrands, B; Kent, AD; Jungwirth, T; Gutfleisch, O; Kim, CG; Berger, A Abstract: (c) 2017 IOP Publishing Ltd. Building upon the success and relevance of the 2014 Magnetism Roadmap, this 2017 Magnetism Roadmap edition follows a similar general layout, even if its focus is naturally shifted, and a different group of experts and, thus, viewpoints are being collected and presented. More importantly, key developments have changed the research landscape in very relevant ways, so that a novel view onto some of the most crucial developments is warranted, and thus, this 2017 Magnetism Roadmap article is a timely endeavour. The change in landscape is hereby not exclusively scientific, but also reflects the magnetism related industrial application portfolio. Specifically, Hard Disk Drive technology, which still dominates digital storage and will continue to do so for many years, if not decades, has now limited its footprint in the scientific and research community, whereas significantly growing interest in magnetism and magnetic materials in relation to energy applications is noticeable, and other technological fields are emerging as well. Also, more and more work is occurring in which complex topologies of magnetically ordered states are being explored, hereby aiming at a technological utilization of the very theoretical concepts that were recognised by the 2016 Nobel Prize in Physics. Given this somewhat shifted scenario, it seemed appropriate to select topics for this Roadmap article that represent the three core pillars of magnetism, namely magnetic materials, magnetic phenomena and associated characterization techniques, as well as applications of magnetism. While many of the contributions in this Roadmap have clearly overlapping relevance in all three fields, their relative focus is mostly associated to one of the three pillars. In this way, the interconnecting roles of having suitable magnetic materials, understanding (and being able to characterize) the underlying physics of their behaviour and utilizing them for applications and devices is well illustrated, thus giving an accurate snapshot of the world of magnetism in 2017. The article consists of 14 sections, each written by an expert in the field and addressing a specific subject on two pages. Evidently, the depth at which each contribution can describe the subject matter is limited and a full review of their statuses, advances, challenges and perspectives cannot be fully accomplished. Also, magnetism, as a vibrant research field, is too diverse, so that a number of areas will not be adequately represented here, leaving space for further Roadmap editions in the future. However, this 2017 Magnetism Roadmap article can provide a frame that will enable the reader to judge where each subject and magnetism research field stands overall today and which directions it might take in the foreseeable future. The first material focused pillar of the 2017 Magnetism Roadmap contains five articles, which address the questions of atomic scale confinement, 2D, curved and topological magnetic materials, as well as materials exhibiting unconventional magnetic phase transitions. The second pillar also has five contributions, which are devoted to advances in magnetic characterization, magneto optics and magneto plasmonics, ultrafast magnetization dynamics and magnonic transport. The final and application focused pillar has four contributions, which present non volatile memory technology, antiferromagnetic spintronics, as well as magnet technology for energy and bio related applications. As a whole, the 2017 Magnetism Roadmap article, just as with its 2014 predecessor, is intended to act as a reference point and guideline for emerging research directions in modern magnetism.
author_names: Daniel J Sander

Sergio O Valenzuela

Denys Makarov

Christopher H Marrows

Eric E Fullerton

Peter Fischer

Jeffrey McCord

Paolo Vavassori

Stephane Mangin

Philipp Pirro

Burkard Hillebrands

Andrew D Kent

Tomas Jungwirth

Oliver Gutfleisch

Cheolgi Kim

Andreas Berger
title: The 2017 Magnetism Roadmap
year: 2017

abstract: Magnetism is a very fascinating and dynamic field. Especially in the last 30 years it has experienced many major advances in the full range from novel fundamental phenomena to new products. Applications such as hard disk drives and magnetic sensors are part of our daily life, and new applications, such as in non volatile computer random access memory, are expected to surface shortly. Thus it is timely for describing the current status, and current and future challenges in the form of a Roadmap article. This 2014 Magnetism Roadmap provides a view on several selected, currently very active innovative developments. It consists of 12 sections, each written by an expert in the field and addressing a specific subject, with strong emphasize on future potential. This Roadmap cannot cover the entire field. We have selected several highly relevant areas without attempting to provide a full review a future update will have room for more topics. The scope covers mostly nano magnetic phenomena and applications, where surfaces and interfaces provide additional functionality. New developments in fundamental topics such as interacting nano elements, novel magnon based spintronics concepts, spin orbit torques and spin caloric phenomena are addressed. New materials, such as organic magnetic materials and permanent magnets are covered. New applications are presented such as nano magnetic logic, non local and domain wall based devices, heat assisted magnetic recording, magnetic random access memory, and applications in biotechnology. May the Roadmap serve as a guideline for future emerging research directions in modern magnetism.
author_names: Robert Stamps

Stephan Breitkreutz

J Aakerman

Andrii V Chumak

Yoshichika Otani

Gerrit E W Bauer

Jan Ulrich Thiele

Martin Bowen

Sara A Majetich

Mathias Klaui

Ioan Lucian Prejbeanu

Bernard Dieny

Nora M Dempsey

Burkard Hillebrands
title: The 2014 Magnetism Roadmap
year: 2014

abstract: Dilute magnetic semiconductors (DMSs) attract tremendous interest as emerging candidates for the microelectronics industry due to their uniqueness in exhibiting spin dependent magneto electro optical properties. Their distinctive material characteristics such as spin dependent coupling between semiconductor bands and the localized states promises magnetoelectric effect the modulation of magnetic properties by an applied electric field in semiconductors (Kulkarni et al. 2005, Ohno et al. 2000) Thus, a wide variety of semiconductor devices can be envisaged (Brunner, 2002a) such as spin polarized lightemitting diodes, lasers (Schulthess and Butler, 2001, Schilfgaarde and Mryasov, 2001) and spin transistor logic devices (Chen et al. 2005, Brunner, 2002b, Ohno et al. 2000) The development of these devices is considered as a possible route for extending the semiconductor scaling roadmap to spin added electronics (Liu et al. 2005)
author_names: Faxian Xiu

Jin Zou

Kang L Wang
title: Magnetic MnxGe1 x Dots for Spintronics Applications
year: 2018

abstract: Two dimensional (2D) hexagonal boron nitride (h BN) is one of the most promising materials for many technological applications ranging from optics to electronics. In past years, a property tunable strategy that involves the construction of electronic structures of h BN through an atomic level design of point defects has been in vogue. The point defects imported during material synthesis or functionalization by defect engineering can endow h BN with new physical characteristics and applications. In this Perspective, we survey the current state of the art in multifunction variations induced by point defects for 2D h BN. We begin with an introduction of the band structure and electronic property of the pristine h BN. Subsequently, the formation and characterization of the most obvious point defects and their modulation in electronic structures of h BN nanomaterials are envisaged in theory. The experimental results obtained by atom resolved transmission electron microscopy, magnetic measurement, and optical measurements have provided insights into the point defect engineered structures and their corresponding emerging properties. Finally, we highlight the perspectives of h BN nanomaterials for heterostructures and devices. This Perspective provides a landscape of the point defect physics involved to demonstrate the modulation of the structure and functionalities in h BN and identify the roadmap for heterostructure and device applications, which will make advances in electronics, spintronics, and nanophotonics.
author_names: Jijun Zhang

Dongliang Ruan

Yanxi Li
title: Point defects in two dimensional hexagonal boron nitride: A perspective
year: 2020

abstract: Molecular/inorganic multilayer heterostructures are gaining attention in molecular electronics and more recently in new generation spintronic devices. The intrinsic properties of molecular materials as low cost, tuneability, or long spin lifetimes were the original reasons behind their implementation. However, the non innocent role played by these hybrid interfaces is a determinant factor in the device performance. In this account we will give an overview about different types of hybrid molecular system/ferromagnet interfaces, which can be of direct application in molecular spintronics. This includes the insertion of a 2D material in between the molecular system and the ferromagnet. As perspective, new hybrid interfaces able to tune the spin properties under an external stimulus, are proposed. These smart interfaces, based on switchable magnetic molecules or flexible MOFs, can open the way to new multifunctional spintronic devices able to couple the spin with a second property.
author_names: Alicia Forment-Aliaga

Eugenio Coronado
title: Hybrid Interfaces in Molecular Spintronics.
venue: Chemical record
year: 2018

abstract: Skyrmionic textures are being extensively investigated due to the occurrence of novel topological magnetic phenomena and their promising applications in a new generation of spintronic devices that take advantage of the robust topological stability of their spin structures. The development of practical devices relies on a detailed understanding of how skyrmionic structures can be formed, transferred, detected and annihilated. In this work, our considerations go beyond static skyrmions and theoretically show that the formation/annihilation of both skyrmions and antiskyrmions is enabled by the transient creation and propagation of topological singularities (magnetic monopole like Bloch points) Critically, during the winding/unwinding of skyrmionic textures, our results predict that the Bloch point propagation will give rise to an emergent electric field in a terahertz frequency range and with substantial amplitude. We also demonstrate ways for controlling Bloch point dynamics, which directly enable the tuneability on both frequency and amplitude of this signal. Our studies provide a concept of directly exploiting topological singularities for terahertz skyrmion based electronic devices.
author_names: Yu Li

Leonardo Pierobon

Michalis Charilaou

H B Braun

Niels R Walet

Jorg F Loffler

Jim J Miles

Christoforos Moutafis
title: Tunable terahertz oscillation arising from Bloch point dynamics in chiral magnets
year: 2019

abstract: (La,Sr)MnO(3) manganite (LSMO) has emerged as the standard ferromagnetic electrode in organic spintronic devices due to its highly spin polarized character and air stability. Whereas organic semiconductors and polymers have been mainly envisaged to propagate spin information, self assembled monolayers (SAMs) have been overlooked and should be considered as promising materials for molecular engineering of spintronic devices. Surprisingly, up to now the first key step of SAM grafting protocols over LSMO surface thin films is still missing. We report the grafting of dodecyl (C12P) and octadecyl (C18P) phosphonic acids over the LSMO half metallic oxide. Alkylphosphonic acids form ordered self assembled monolayers, with the phosphonic group coordinated to the surface and alkyl chains tilted from the surface vertical by 43deg (C12P) and 27deg (C18P) We have electrically characterized these SAMs in nanodevices and found that they act as tunnel barriers, opening the door toward the integration of alkylphosphonic acid//LSMO SAMs into future molecular/organic spintronic devices such as spin OLEDs.
author_names: Sergio Tatay

Clement Barraud

Marta Galbiati

Pierre Seneor

Richard Mattana

Karim Bouzehouane

Cyrile Deranlot

Eric Jacquet

Alicia Forment-Aliaga

Pascale Jegou

Albert Fert

Fr'ed'eric Petroff
title: Self assembled monolayer functionalized half metallic manganite for molecular spintronics.
venue: ACS nano
year: 2012