Magnetoelectric coupling lights up spintronics path: Lithium battery ideas to tune magnetism

Abstract

While materials phenomena can be exploited in laboratories for scientific purposes, real-world applications require levels of stability, efficiency, and control. Recent work by Li et al. demonstrates a magnetoelectric effect originating from the spin capacitance, combining the advantages of intercalation batteries and supercapacitors and advancing ultralow-power memory and sensor technologies. While materials phenomena can be exploited in laboratories for scientific purposes, real-world applications require levels of stability, efficiency, and control. Recent work by Li et al. demonstrates a magnetoelectric effect originating from the spin capacitance, combining the advantages of intercalation batteries and supercapacitors and advancing ultralow-power memory and sensor technologies. Main textThe realization of magnetic tunnel junction (MTJ)—a sandwich device consisting of two ferromagnetic layers with an ultrathin insulating barrier in between—in 1995 soon found widespread application as the read sensor in hard disk drives for unprecedented ultrahigh dense data storage in computers and iPods and as non-volatile memories, reaching out in automotive applications and outer space.1Moodera J.S. Miao G.X. Santos T.S. Frontiers in spin-polarized tunneling.Phys. Today. 2010; 63: 46Crossref Scopus (57) Google Scholar,2Hirohata A. Yamada K. Nakatani Y. Prejbeanu I.L. Diény B. Pirro P. Hillebrands B. Review on spintronics: Principles and device applications.J. Magn. Magn. Mater. 2020; 509: 166711Crossref Scopus (360) Google Scholar Its potential is anticipated to extend even further into in-memory computing, neural networking, and artificial intelligence. One of the roadblocks in further implementation of MTJs in spintronics is the efficient and fast switching of the magnetic layer with low energy dissipation. Among other approaches, the work of Li et al. is showing an exciting, low energy switching/control path forward.3Zhang F. Li Z. Xia Q. Zhang Q. Ge C. Chen Y. Li X. Zhang L. Wang K. Li H. et al.Li-ionic control of magnetism through spin capacitance and conversion.Matter. 2021; 4: 3605-3620https://doi.org/10.1016/j.matt.2021.09.006Abstract Full Text Full Text PDF Scopus (9) Google ScholarEffectively controlling the magnetic properties of materials with external electric fields is one promising way to promote the development of low-power spintronic applications.4Ohno H. Chiba D. Matsukura F. Omiya T. Abe E. Dietl T. Ohno Y. Ohtani K. Electric-field control of ferromagnetism.Nature. 2000; 408: 944-946Crossref PubMed Scopus (1846) Google Scholar There have been many approaches successfully realized to regulate the magnetic properties in various material systems, and they have shown splendors in neuromorphic computing, information storage, electrochemical sensing, and much more.5Noël P. Trier F. Vicente Arche L.M. Bréhin J. Vaz D.C. Garcia V. Fusil S. Barthélémy A. Vila L. Bibes M. Attané J.P. Non-volatile electric control of spin-charge conversion in a SrTiO3 Rashba system.Nature. 2020; 580: 483-486Crossref PubMed Scopus (82) Google Scholar,6Deng Y. Yu Y. Song Y. Zhang J. Wang N.Z. Sun Z. Yi Y. Wu Y.Z. Wu S. Zhu J. et al.Gate-tunable room-temperature ferromagnetism in two-dimensional Fe3GeTe2.Nature. 2018; 563: 94-99Crossref PubMed Scopus (1031) Google Scholar More effective regulation mechanisms need to be excavated with the increasing demand for low-power and high-efficiency devices in modern society. In recent years, magneto-electric control with concepts borrowed from the working principles of ion batteries and capacitors has reached certain milestones,7Weisheit M. Fähler S. Marty A. Souche Y. Poinsignon C. Givord D. Electric field-induced modification of magnetism in thin-film ferromagnets.Science. 2007; 315: 349-351Crossref PubMed Scopus (925) Google Scholar,8Dasgupta S. Das B. Knapp M. Brand R.A. Ehrenberg H. Kruk R. Hahn H. Intercalation-driven reversible control of magnetism in bulk ferromagnets.Adv. Mater. 2014; 26: 4639-4644Crossref PubMed Scopus (74) Google Scholar but it still cannot achieve satisfactory control in the modulation depth—achieving reversibility and stability at the same time. Writing in Matter, Li and colleagues from China and Canada skillfully utilized the spin capacitance effect, deriving knowledge from ion batteries and capacitors, to influence ferromagnet interfaces to achieve giant, fast, stable, and reversible magneto-electric control.With careful characterizations, it is proven that the reversible magnetic response is derived from the modulated charge and spin distribution on the ferromagnet interfaces, establishing the direct connection between charge storage and magnetic control (Figure 1). The researchers also realized good magneto-electric tuning effect in different material systems, and the saturation magnetization variation is as high as 0.31 μB per Fe atom, proving that the tuning mechanism based on spin capacitance is universal and has application prospects in ultralow-power logic, sensor, and neuromorphic computing applications. Taking advantage of the powerful operando magnetometry, the researchers furthermore found that the oxidation product FeO retains significant ferromagnetic characteristics owing to the surface reconstruction. This fundamental observation clarifies a long dispute in magnetism, and the attempts in this work provide important references for the design and cognition of spintronics to even higher levels.While it is highly encouraging to be able to manipulate the magnetic layer properties at such small voltages, thereby nearly solving the power issue, the tuning speed is something that goes in the wrong direction. In other words, having to move the ions across thicker insulating layers (electrolytes) to reach the interface evidently comes with a price on speed. The fact that the ions move slowly and have to travel some distance renders the device switching to be relatively slow: ions move orders of magnitude slower compared to electrons, so it would be hard to compete with spin-transfer torque (STT)9Ralph D.C. Stiles M.D. Spin transfer torques.J. Magn. Magn. Mater. 2008; 320: 1190-1216Crossref Scopus (1294) Google Scholar or spin-orbit torque (SOT)10Manchon A. Železný J. Miron I.M. Jungwirth T. Sinova J. Thiaville A. Garello K. Gambardella P. Current-induced spin-orbit torques in ferromagnetic and antiferromagnetic systems.Rev. Mod. Phys. 2019; 91: 035004Crossref Scopus (543) Google Scholar for switching in speed. However, where speed is not a defining criterion, such as in persistent modes (like reprogramming), this approach would be useful. To gain speed, one can think of ions that go faster, for example, H ions, and also reduce the thickness of the diffusion layer so the ions need to move only one or two atomic layers instead of many tens of layers, besides controlling its material properties to allow for faster diffusion. Or, even better, one could use strongly polar molecules wherein the dipolar orientation may be changed quickly and effectively with small electric fields. Main textThe realization of magnetic tunnel junction (MTJ)—a sandwich device consisting of two ferromagnetic layers with an ultrathin insulating barrier in between—in 1995 soon found widespread application as the read sensor in hard disk drives for unprecedented ultrahigh dense data storage in computers and iPods and as non-volatile memories, reaching out in automotive applications and outer space.1Moodera J.S. Miao G.X. Santos T.S. Frontiers in spin-polarized tunneling.Phys. Today. 2010; 63: 46Crossref Scopus (57) Google Scholar,2Hirohata A. Yamada K. Nakatani Y. Prejbeanu I.L. Diény B. Pirro P. Hillebrands B. Review on spintronics: Principles and device applications.J. Magn. Magn. Mater. 2020; 509: 166711Crossref Scopus (360) Google Scholar Its potential is anticipated to extend even further into in-memory computing, neural networking, and artificial intelligence. One of the roadblocks in further implementation of MTJs in spintronics is the efficient and fast switching of the magnetic layer with low energy dissipation. Among other approaches, the work of Li et al. is showing an exciting, low energy switching/control path forward.3Zhang F. Li Z. Xia Q. Zhang Q. Ge C. Chen Y. Li X. Zhang L. Wang K. Li H. et al.Li-ionic control of magnetism through spin capacitance and conversion.Matter. 2021; 4: 3605-3620https://doi.org/10.1016/j.matt.2021.09.006Abstract Full Text Full Text PDF Scopus (9) Google ScholarEffectively controlling the magnetic properties of materials with external electric fields is one promising way to promote the development of low-power spintronic applications.4Ohno H. Chiba D. Matsukura F. Omiya T. Abe E. Dietl T. Ohno Y. Ohtani K. Electric-field control of ferromagnetism.Nature. 2000; 408: 944-946Crossref PubMed Scopus (1846) Google Scholar There have been many approaches successfully realized to regulate the magnetic properties in various material systems, and they have shown splendors in neuromorphic computing, information storage, electrochemical sensing, and much more.5Noël P. Trier F. Vicente Arche L.M. Bréhin J. Vaz D.C. Garcia V. Fusil S. Barthélémy A. Vila L. Bibes M. Attané J.P. Non-volatile electric control of spin-charge conversion in a SrTiO3 Rashba system.Nature. 2020; 580: 483-486Crossref PubMed Scopus (82) Google Scholar,6Deng Y. Yu Y. Song Y. Zhang J. Wang N.Z. Sun Z. Yi Y. Wu Y.Z. Wu S. Zhu J. et al.Gate-tunable room-temperature ferromagnetism in two-dimensional Fe3GeTe2.Nature. 2018; 563: 94-99Crossref PubMed Scopus (1031) Google Scholar More effective regulation mechanisms need to be excavated with the increasing demand for low-power and high-efficiency devices in modern society. In recent years, magneto-electric control with concepts borrowed from the working principles of ion batteries and capacitors has reached certain milestones,7Weisheit M. Fähler S. Marty A. Souche Y. Poinsignon C. Givord D. Electric field-induced modification of magnetism in thin-film ferromagnets.Science. 2007; 315: 349-351Crossref PubMed Scopus (925) Google Scholar,8Dasgupta S. Das B. Knapp M. Brand R.A. Ehrenberg H. Kruk R. Hahn H. Intercalation-driven reversible control of magnetism in bulk ferromagnets.Adv. Mater. 2014; 26: 4639-4644Crossref PubMed Scopus (74) Google Scholar but it still cannot achieve satisfactory control in the modulation depth—achieving reversibility and stability at the same time. Writing in Matter, Li and colleagues from China and Canada skillfully utilized the spin capacitance effect, deriving knowledge from ion batteries and capacitors, to influence ferromagnet interfaces to achieve giant, fast, stable, and reversible magneto-electric control.With careful characterizations, it is proven that the reversible magnetic response is derived from the modulated charge and spin distribution on the ferromagnet interfaces, establishing the direct connection between charge storage and magnetic control (Figure 1). The researchers also realized good magneto-electric tuning effect in different material systems, and the saturation magnetization variation is as high as 0.31 μB per Fe atom, proving that the tuning mechanism based on spin capacitance is universal and has application prospects in ultralow-power logic, sensor, and neuromorphic computing applications. Taking advantage of the powerful operando magnetometry, the researchers furthermore found that the oxidation product FeO retains significant ferromagnetic characteristics owing to the surface reconstruction. This fundamental observation clarifies a long dispute in magnetism, and the attempts in this work provide important references for the design and cognition of spintronics to even higher levels.While it is highly encouraging to be able to manipulate the magnetic layer properties at such small voltages, thereby nearly solving the power issue, the tuning speed is something that goes in the wrong direction. In other words, having to move the ions across thicker insulating layers (electrolytes) to reach the interface evidently comes with a price on speed. The fact that the ions move slowly and have to travel some distance renders the device switching to be relatively slow: ions move orders of magnitude slower compared to electrons, so it would be hard to compete with spin-transfer torque (STT)9Ralph D.C. Stiles M.D. Spin transfer torques.J. Magn. Magn. Mater. 2008; 320: 1190-1216Crossref Scopus (1294) Google Scholar or spin-orbit torque (SOT)10Manchon A. Železný J. Miron I.M. Jungwirth T. Sinova J. Thiaville A. Garello K. Gambardella P. Current-induced spin-orbit torques in ferromagnetic and antiferromagnetic systems.Rev. Mod. Phys. 2019; 91: 035004Crossref Scopus (543) Google Scholar for switching in speed. However, where speed is not a defining criterion, such as in persistent modes (like reprogramming), this approach would be useful. To gain speed, one can think of ions that go faster, for example, H ions, and also reduce the thickness of the diffusion layer so the ions need to move only one or two atomic layers instead of many tens of layers, besides controlling its material properties to allow for faster diffusion. Or, even better, one could use strongly polar molecules wherein the dipolar orientation may be changed quickly and effectively with small electric fields. The realization of magnetic tunnel junction (MTJ)—a sandwich device consisting of two ferromagnetic layers with an ultrathin insulating barrier in between—in 1995 soon found widespread application as the read sensor in hard disk drives for unprecedented ultrahigh dense data storage in computers and iPods and as non-volatile memories, reaching out in automotive applications and outer space.1Moodera J.S. Miao G.X. Santos T.S. Frontiers in spin-polarized tunneling.Phys. Today. 2010; 63: 46Crossref Scopus (57) Google Scholar,2Hirohata A. Yamada K. Nakatani Y. Prejbeanu I.L. Diény B. Pirro P. Hillebrands B. Review on spintronics: Principles and device applications.J. Magn. Magn. Mater. 2020; 509: 166711Crossref Scopus (360) Google Scholar Its potential is anticipated to extend even further into in-memory computing, neural networking, and artificial intelligence. One of the roadblocks in further implementation of MTJs in spintronics is the efficient and fast switching of the magnetic layer with low energy dissipation. Among other approaches, the work of Li et al. is showing an exciting, low energy switching/control path forward.3Zhang F. Li Z. Xia Q. Zhang Q. Ge C. Chen Y. Li X. Zhang L. Wang K. Li H. et al.Li-ionic control of magnetism through spin capacitance and conversion.Matter. 2021; 4: 3605-3620https://doi.org/10.1016/j.matt.2021.09.006Abstract Full Text Full Text PDF Scopus (9) Google Scholar Effectively controlling the magnetic properties of materials with external electric fields is one promising way to promote the development of low-power spintronic applications.4Ohno H. Chiba D. Matsukura F. Omiya T. Abe E. Dietl T. Ohno Y. Ohtani K. Electric-field control of ferromagnetism.Nature. 2000; 408: 944-946Crossref PubMed Scopus (1846) Google Scholar There have been many approaches successfully realized to regulate the magnetic properties in various material systems, and they have shown splendors in neuromorphic computing, information storage, electrochemical sensing, and much more.5Noël P. Trier F. Vicente Arche L.M. Bréhin J. Vaz D.C. Garcia V. Fusil S. Barthélémy A. Vila L. Bibes M. Attané J.P. Non-volatile electric control of spin-charge conversion in a SrTiO3 Rashba system.Nature. 2020; 580: 483-486Crossref PubMed Scopus (82) Google Scholar,6Deng Y. Yu Y. Song Y. Zhang J. Wang N.Z. Sun Z. Yi Y. Wu Y.Z. Wu S. Zhu J. et al.Gate-tunable room-temperature ferromagnetism in two-dimensional Fe3GeTe2.Nature. 2018; 563: 94-99Crossref PubMed Scopus (1031) Google Scholar More effective regulation mechanisms need to be excavated with the increasing demand for low-power and high-efficiency devices in modern society. In recent years, magneto-electric control with concepts borrowed from the working principles of ion batteries and capacitors has reached certain milestones,7Weisheit M. Fähler S. Marty A. Souche Y. Poinsignon C. Givord D. Electric field-induced modification of magnetism in thin-film ferromagnets.Science. 2007; 315: 349-351Crossref PubMed Scopus (925) Google Scholar,8Dasgupta S. Das B. Knapp M. Brand R.A. Ehrenberg H. Kruk R. Hahn H. Intercalation-driven reversible control of magnetism in bulk ferromagnets.Adv. Mater. 2014; 26: 4639-4644Crossref PubMed Scopus (74) Google Scholar but it still cannot achieve satisfactory control in the modulation depth—achieving reversibility and stability at the same time. Writing in Matter, Li and colleagues from China and Canada skillfully utilized the spin capacitance effect, deriving knowledge from ion batteries and capacitors, to influence ferromagnet interfaces to achieve giant, fast, stable, and reversible magneto-electric control. With careful characterizations, it is proven that the reversible magnetic response is derived from the modulated charge and spin distribution on the ferromagnet interfaces, establishing the direct connection between charge storage and magnetic control (Figure 1). The researchers also realized good magneto-electric tuning effect in different material systems, and the saturation magnetization variation is as high as 0.31 μB per Fe atom, proving that the tuning mechanism based on spin capacitance is universal and has application prospects in ultralow-power logic, sensor, and neuromorphic computing applications. Taking advantage of the powerful operando magnetometry, the researchers furthermore found that the oxidation product FeO retains significant ferromagnetic characteristics owing to the surface reconstruction. This fundamental observation clarifies a long dispute in magnetism, and the attempts in this work provide important references for the design and cognition of spintronics to even higher levels. While it is highly encouraging to be able to manipulate the magnetic layer properties at such small voltages, thereby nearly solving the power issue, the tuning speed is something that goes in the wrong direction. In other words, having to move the ions across thicker insulating layers (electrolytes) to reach the interface evidently comes with a price on speed. The fact that the ions move slowly and have to travel some distance renders the device switching to be relatively slow: ions move orders of magnitude slower compared to electrons, so it would be hard to compete with spin-transfer torque (STT)9Ralph D.C. Stiles M.D. Spin transfer torques.J. Magn. Magn. Mater. 2008; 320: 1190-1216Crossref Scopus (1294) Google Scholar or spin-orbit torque (SOT)10Manchon A. Železný J. Miron I.M. Jungwirth T. Sinova J. Thiaville A. Garello K. Gambardella P. Current-induced spin-orbit torques in ferromagnetic and antiferromagnetic systems.Rev. Mod. Phys. 2019; 91: 035004Crossref Scopus (543) Google Scholar for switching in speed. However, where speed is not a defining criterion, such as in persistent modes (like reprogramming), this approach would be useful. To gain speed, one can think of ions that go faster, for example, H ions, and also reduce the thickness of the diffusion layer so the ions need to move only one or two atomic layers instead of many tens of layers, besides controlling its material properties to allow for faster diffusion. Or, even better, one could use strongly polar molecules wherein the dipolar orientation may be changed quickly and effectively with small electric fields. Li-ionic control of magnetism through spin capacitance and conversionZhang et al.MatterSeptember 23, 2021In BriefThe magnetic properties of materials are controlled under the actuation of electric field, which is the so-called magnetoelectric coupling effect, and it has an essential role in the fields of spintronics and storage applications. This study skillfully utilizes the space charge phenomenon at the interface between ferromagnetic metal and ionic conductor, showing a completely reversible, stable, and robust magnetic regulation effect under the combined effect of magnetic field and electric field. Full-Text PDF Open Archive