Pub Date : 2024-11-06DOI: 10.1038/s44306-024-00058-9
Diana C. Leitao, Floris J. F. van Riel, Mahmoud Rasly, Pedro D. R. Araujo, Maria Salvador, Elvira Paz, Bert Koopmans
Spintronic sensors are uniquely positioned to deliver the next generation of high-performance magnetic field measurement tools with re-configurable key features. In this perspective article, we focus on giant and tunnel magnetoresistance sensors that exploit changes in the electrical resistance of thin films in response to an external magnetic field. We discuss strategies to address ongoing open challenges to improve operation limits. The goal is to meet current technological needs and thus expand the scope of existing applications. We also propose innovative approaches to design sensors with adaptable characteristics and embedded multifunctionality, aiming to create opportunities for future magnetic sensing applications. These solutions leverage the versatility of spintronic sensors, from the thin-film multilayers that form their building blocks, to device fabrication methods and potential integration with other technologies. The outlook of novel applications spans multiple areas, including electric vehicles, robotics, remote detection, or biomedicine.
{"title":"Enhanced performance and functionality in spintronic sensors","authors":"Diana C. Leitao, Floris J. F. van Riel, Mahmoud Rasly, Pedro D. R. Araujo, Maria Salvador, Elvira Paz, Bert Koopmans","doi":"10.1038/s44306-024-00058-9","DOIUrl":"10.1038/s44306-024-00058-9","url":null,"abstract":"Spintronic sensors are uniquely positioned to deliver the next generation of high-performance magnetic field measurement tools with re-configurable key features. In this perspective article, we focus on giant and tunnel magnetoresistance sensors that exploit changes in the electrical resistance of thin films in response to an external magnetic field. We discuss strategies to address ongoing open challenges to improve operation limits. The goal is to meet current technological needs and thus expand the scope of existing applications. We also propose innovative approaches to design sensors with adaptable characteristics and embedded multifunctionality, aiming to create opportunities for future magnetic sensing applications. These solutions leverage the versatility of spintronic sensors, from the thin-film multilayers that form their building blocks, to device fabrication methods and potential integration with other technologies. The outlook of novel applications spans multiple areas, including electric vehicles, robotics, remote detection, or biomedicine.","PeriodicalId":501713,"journal":{"name":"npj Spintronics","volume":" ","pages":"1-11"},"PeriodicalIF":0.0,"publicationDate":"2024-11-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.nature.com/articles/s44306-024-00058-9.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142588298","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-11-06DOI: 10.1038/s44306-024-00059-8
Kemal Selcuk, Saleh Bunaiyan, Nihal Sanjay Singh, Shehrin Sayed, Samiran Ganguly, Giovanni Finocchio, Supriyo Datta, Kerem Y. Camsari
An emerging paradigm in modern electronics is that of CMOS+ $${mathsf{X}}$$ requiring the integration of standard CMOS technology with novel materials and technologies denoted by $${mathsf{X}}$$ . In this context, a crucial challenge is to develop accurate circuit models for $${mathsf{X}}$$ that are compatible with standard models for CMOS-based circuits and systems. In this perspective, we present physics-based, experimentally benchmarked modular circuit models that can be used to evaluate a class of CMOS+ $${mathsf{X}}$$ systems, where $${mathsf{X}}$$ denotes magnetic and spintronic materials and phenomena. This class of materials is particularly challenging because they go beyond conventional charge-based phenomena and involve the spin degree of freedom which involves non-trivial quantum effects. Starting from density matrices—the central quantity in quantum transport—using well-defined approximations, it is possible to obtain spin-circuits that generalize ordinary circuit theory to 4-component currents and voltages (1 for charge and 3 for spin). With step-by-step examples that progressively become more complex, we illustrate how the spin-circuit approach can be used to start from the physics of magnetism and spintronics to enable accurate system-level evaluations. We believe the core approach can be extended to include other quantum degrees of freedom like valley and pseudospins starting from corresponding density matrices.
{"title":"Connecting physics to systems with modular spin-circuits","authors":"Kemal Selcuk, Saleh Bunaiyan, Nihal Sanjay Singh, Shehrin Sayed, Samiran Ganguly, Giovanni Finocchio, Supriyo Datta, Kerem Y. Camsari","doi":"10.1038/s44306-024-00059-8","DOIUrl":"10.1038/s44306-024-00059-8","url":null,"abstract":"An emerging paradigm in modern electronics is that of CMOS+ $${mathsf{X}}$$ requiring the integration of standard CMOS technology with novel materials and technologies denoted by $${mathsf{X}}$$ . In this context, a crucial challenge is to develop accurate circuit models for $${mathsf{X}}$$ that are compatible with standard models for CMOS-based circuits and systems. In this perspective, we present physics-based, experimentally benchmarked modular circuit models that can be used to evaluate a class of CMOS+ $${mathsf{X}}$$ systems, where $${mathsf{X}}$$ denotes magnetic and spintronic materials and phenomena. This class of materials is particularly challenging because they go beyond conventional charge-based phenomena and involve the spin degree of freedom which involves non-trivial quantum effects. Starting from density matrices—the central quantity in quantum transport—using well-defined approximations, it is possible to obtain spin-circuits that generalize ordinary circuit theory to 4-component currents and voltages (1 for charge and 3 for spin). With step-by-step examples that progressively become more complex, we illustrate how the spin-circuit approach can be used to start from the physics of magnetism and spintronics to enable accurate system-level evaluations. We believe the core approach can be extended to include other quantum degrees of freedom like valley and pseudospins starting from corresponding density matrices.","PeriodicalId":501713,"journal":{"name":"npj Spintronics","volume":" ","pages":"1-12"},"PeriodicalIF":0.0,"publicationDate":"2024-11-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.nature.com/articles/s44306-024-00059-8.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142588299","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-10-26DOI: 10.1038/s44306-024-00056-x
Po-Hao Chang, Igor I. Mazin
Magnetism in the Zintl compound Ba14MnBi11 is rather poorly understood. Experimental claims are largely inconsistent with ab initio calculations, much beyond typical errors of the latter. We revisit this old problem, assuming that the root of the problem may be in nonstoichiometry of existing samples. Our key finding is that the magnetic ground state is indeed very susceptible to charge doping (band filling). Calculations for stoichiometric Ba14MnBi11 give a rather stable ferromagnetic metallic state, in agreement with previous publications. However, by adding exactly one electron per Mn, the system becomes semiconducting as expected, and becomes weakly antiferromagnetic (AF). On the other hand, upon small amount of hole doping, the system transitions to a special type of AF state known as altermagnetism. Furthermore, hole and electron doping-induced phase transitions result from different underlying mechanisms, influencing different exchange pathways. We propose that the inconsistency between experiment and theory is not a failure of the latter, but results from a nontrivial ramification of nonstoichiometry. The possibility of doping-stabilized altermagnetism is exciting.
人们对 Zintl 化合物 Ba14MnBi11 的磁性了解甚少。实验结果在很大程度上与 ab initio 计算结果不一致，远远超出了后者的典型误差。我们重新审视了这个老问题，假设问题的根源可能在于现有样品的非化学计量。我们的主要发现是，磁基态确实非常容易受到电荷掺杂（带填充）的影响。通过计算化学计量 Ba14MnBi11，可以得到相当稳定的铁磁金属态，这与之前发表的文章一致。然而，当每锰恰好加入一个电子时，该体系就会如预期的那样成为半导体，并变成弱反铁磁性（AF）。另一方面，当掺入少量空穴时，体系会过渡到一种特殊的反铁磁性（AF）状态，即所谓的 "变磁"（altermagnetism）。此外，空穴掺杂和电子掺杂诱导的相变产生于不同的基本机制，影响着不同的交换途径。我们提出，实验与理论之间的不一致并不是理论的失败，而是由于非化学计量学的非微不足道的衍生物造成的。掺杂稳定变磁性的可能性令人兴奋。
{"title":"The mysterious magnetic ground state of Ba14MnBi11 is likely self-doped and altermagnetic","authors":"Po-Hao Chang, Igor I. Mazin","doi":"10.1038/s44306-024-00056-x","DOIUrl":"10.1038/s44306-024-00056-x","url":null,"abstract":"Magnetism in the Zintl compound Ba14MnBi11 is rather poorly understood. Experimental claims are largely inconsistent with ab initio calculations, much beyond typical errors of the latter. We revisit this old problem, assuming that the root of the problem may be in nonstoichiometry of existing samples. Our key finding is that the magnetic ground state is indeed very susceptible to charge doping (band filling). Calculations for stoichiometric Ba14MnBi11 give a rather stable ferromagnetic metallic state, in agreement with previous publications. However, by adding exactly one electron per Mn, the system becomes semiconducting as expected, and becomes weakly antiferromagnetic (AF). On the other hand, upon small amount of hole doping, the system transitions to a special type of AF state known as altermagnetism. Furthermore, hole and electron doping-induced phase transitions result from different underlying mechanisms, influencing different exchange pathways. We propose that the inconsistency between experiment and theory is not a failure of the latter, but results from a nontrivial ramification of nonstoichiometry. The possibility of doping-stabilized altermagnetism is exciting.","PeriodicalId":501713,"journal":{"name":"npj Spintronics","volume":" ","pages":"1-7"},"PeriodicalIF":0.0,"publicationDate":"2024-10-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.nature.com/articles/s44306-024-00056-x.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142519198","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-10-14DOI: 10.1038/s44306-024-00060-1
Qiming Shao
Increasing the bandwidth of existing optical fiber networks is vital as society’s appetite for information grows. This Editorial presents a spintronics-based solution in the context of recent research findings.
{"title":"Communicating with magnons","authors":"Qiming Shao","doi":"10.1038/s44306-024-00060-1","DOIUrl":"10.1038/s44306-024-00060-1","url":null,"abstract":"Increasing the bandwidth of existing optical fiber networks is vital as society’s appetite for information grows. This Editorial presents a spintronics-based solution in the context of recent research findings.","PeriodicalId":501713,"journal":{"name":"npj Spintronics","volume":" ","pages":"1-1"},"PeriodicalIF":0.0,"publicationDate":"2024-10-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.nature.com/articles/s44306-024-00060-1.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142431069","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-10-05DOI: 10.1038/s44306-024-00055-y
Philipp Keßler, Laura Garcia-Gassull, Andreas Suter, Thomas Prokscha, Zaher Salman, Dmitry Khalyavin, Pascal Manuel, Fabio Orlandi, Igor I. Mazin, Roser Valentí, Simon Moser
Altermagnets are a novel class of magnetic materials, where magnetic order is staggered both in coordinate and momentum space. The metallic rutile oxide RuO2, long believed to be a textbook Pauli paramagnet, recently emerged as a putative workhorse altermagnet when resonant X-ray and neutron scattering studies reported nonzero magnetic moments and long-range collinear order. While some experiments seem consistent with altermagnetism, magnetic order in RuO2 remains controversial. We show that RuO2 is nonmagnetic, both in bulk and thin film. Muon spectroscopy complemented by density-functional theory finds at most 1.14 × 10−4 μB/Ru in bulk and at most 7.5 × 10−4 μB/Ru in 11 nm epitaxial films, at our spectrometers’ detection limit, and dramatically smaller than previously reported neutron results that were used to rationalize altermagnetic behavior. Our own neutron diffraction measurements on RuO2 single crystals identify multiple scattering as the source for the false signal in earlier studies.
{"title":"Absence of magnetic order in RuO2: insights from μSR spectroscopy and neutron diffraction","authors":"Philipp Keßler, Laura Garcia-Gassull, Andreas Suter, Thomas Prokscha, Zaher Salman, Dmitry Khalyavin, Pascal Manuel, Fabio Orlandi, Igor I. Mazin, Roser Valentí, Simon Moser","doi":"10.1038/s44306-024-00055-y","DOIUrl":"10.1038/s44306-024-00055-y","url":null,"abstract":"Altermagnets are a novel class of magnetic materials, where magnetic order is staggered both in coordinate and momentum space. The metallic rutile oxide RuO2, long believed to be a textbook Pauli paramagnet, recently emerged as a putative workhorse altermagnet when resonant X-ray and neutron scattering studies reported nonzero magnetic moments and long-range collinear order. While some experiments seem consistent with altermagnetism, magnetic order in RuO2 remains controversial. We show that RuO2 is nonmagnetic, both in bulk and thin film. Muon spectroscopy complemented by density-functional theory finds at most 1.14 × 10−4 μB/Ru in bulk and at most 7.5 × 10−4 μB/Ru in 11 nm epitaxial films, at our spectrometers’ detection limit, and dramatically smaller than previously reported neutron results that were used to rationalize altermagnetic behavior. Our own neutron diffraction measurements on RuO2 single crystals identify multiple scattering as the source for the false signal in earlier studies.","PeriodicalId":501713,"journal":{"name":"npj Spintronics","volume":" ","pages":"1-8"},"PeriodicalIF":0.0,"publicationDate":"2024-10-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.nature.com/articles/s44306-024-00055-y.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142383564","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-10-01DOI: 10.1038/s44306-024-00044-1
V. D. Nguyen, S. Rao, K. Wostyn, S. Couet
Spin-orbit torque magnetic random-access memory (SOT-MRAM) offers promise for fast operation and high endurance but faces challenges such as low switching current, reliable field free switching, and back-end of line manufacturing processes. We review recent advancements in perpendicular SOT-MRAM devices, emphasizing on material developments to enhance charge-spin conversion efficiency and large-scale device integration strategies. We also discuss the remaining challenges in achieving a single device with low switching current, reliable field free switching to unlock the full potential of SOT-MRAM technology.
{"title":"Recent progress in spin-orbit torque magnetic random-access memory","authors":"V. D. Nguyen, S. Rao, K. Wostyn, S. Couet","doi":"10.1038/s44306-024-00044-1","DOIUrl":"10.1038/s44306-024-00044-1","url":null,"abstract":"Spin-orbit torque magnetic random-access memory (SOT-MRAM) offers promise for fast operation and high endurance but faces challenges such as low switching current, reliable field free switching, and back-end of line manufacturing processes. We review recent advancements in perpendicular SOT-MRAM devices, emphasizing on material developments to enhance charge-spin conversion efficiency and large-scale device integration strategies. We also discuss the remaining challenges in achieving a single device with low switching current, reliable field free switching to unlock the full potential of SOT-MRAM technology.","PeriodicalId":501713,"journal":{"name":"npj Spintronics","volume":" ","pages":"1-15"},"PeriodicalIF":0.0,"publicationDate":"2024-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.nature.com/articles/s44306-024-00044-1.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142360067","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Achieving the full understanding and control of the insulator-to-metal transition in Mott materials is key for the next generation of electronics devices, with applications ranging from ultrafast transistors, volatile and non-volatile memories and artificial neurons for neuromorphic computing. In this work, we will review the state-of-the-art knowledge of the Mott transition, with specific focus on materials of relevance for actual devices, such as vanadium and other transition metal oxides and chalcogenides. We will emphasize the current attempts in controlling the Mott switching dynamics via the application of external voltage and electromagnetic pulses and we will discuss how the recent advances in time- and space-resolved techniques are boosting the comprehension of the firing process. The nature of the voltage/light-induced Mott switching is inherently different from what is attainable by the slower variation of thermodynamic parameters, thus offering promising routes to achieving the reversible and ultrafast control of conductivity and magnetism in Mott nanodevices.
{"title":"Mott materials: unsuccessful metals with a bright future","authors":"Alessandra Milloch, Michele Fabrizio, Claudio Giannetti","doi":"10.1038/s44306-024-00047-y","DOIUrl":"10.1038/s44306-024-00047-y","url":null,"abstract":"Achieving the full understanding and control of the insulator-to-metal transition in Mott materials is key for the next generation of electronics devices, with applications ranging from ultrafast transistors, volatile and non-volatile memories and artificial neurons for neuromorphic computing. In this work, we will review the state-of-the-art knowledge of the Mott transition, with specific focus on materials of relevance for actual devices, such as vanadium and other transition metal oxides and chalcogenides. We will emphasize the current attempts in controlling the Mott switching dynamics via the application of external voltage and electromagnetic pulses and we will discuss how the recent advances in time- and space-resolved techniques are boosting the comprehension of the firing process. The nature of the voltage/light-induced Mott switching is inherently different from what is attainable by the slower variation of thermodynamic parameters, thus offering promising routes to achieving the reversible and ultrafast control of conductivity and magnetism in Mott nanodevices.","PeriodicalId":501713,"journal":{"name":"npj Spintronics","volume":" ","pages":"1-10"},"PeriodicalIF":0.0,"publicationDate":"2024-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.nature.com/articles/s44306-024-00047-y.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142360068","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Magnons and phonons are engineered in artificial lattices with tunable modes and band dispersions. Recent advance in magnon-phonon coupling shined a light on combining magnonic and phononic crystals as hybrid magnon-phonon crystals, benefit from the tunable magnon-phonon coupling, the time-reversal symmetry breaking of magnons, and the long lifetime of phonons. This perspective summarizes lattice-based mutual control of magnons and phonons, and proposes the opportunities provided by the hybrid magnon-phonon crystals.
{"title":"Hybrid magnon-phonon crystals","authors":"Liyang Liao, Jiacheng Liu, Jorge Puebla, Qiming Shao, Yoshichika Otani","doi":"10.1038/s44306-024-00052-1","DOIUrl":"10.1038/s44306-024-00052-1","url":null,"abstract":"Magnons and phonons are engineered in artificial lattices with tunable modes and band dispersions. Recent advance in magnon-phonon coupling shined a light on combining magnonic and phononic crystals as hybrid magnon-phonon crystals, benefit from the tunable magnon-phonon coupling, the time-reversal symmetry breaking of magnons, and the long lifetime of phonons. This perspective summarizes lattice-based mutual control of magnons and phonons, and proposes the opportunities provided by the hybrid magnon-phonon crystals.","PeriodicalId":501713,"journal":{"name":"npj Spintronics","volume":" ","pages":"1-6"},"PeriodicalIF":0.0,"publicationDate":"2024-09-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.nature.com/articles/s44306-024-00052-1.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142137874","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-09-02DOI: 10.1038/s44306-024-00053-0
Theodoros Adamantopoulos, Maximilian Merte, Frank Freimuth, Dongwook Go, Lishu Zhang, Marjana Ležaić, Wanxiang Feng, Yugui Yao, Jairo Sinova, Libor Šmejkal, Stefan Blügel, Yuriy Mokrousov
While the understanding of altermagnetism is still at a very early stage, it is expected to play a role in various fields of condensed matter research, for example spintronics, caloritronics and superconductivity. In the field of optical magnetism, it is still unclear to which extent altermagnets as a class can exhibit a distinct behavior. Here we choose RuO2, a prototype metallic altermagnet with a giant spin splitting, and CoF2, an experimentally known insulating altermagnet, to study the light-induced magnetism in rutile altermagnets from first-principles. We demonstrate that in the non-relativisic limit the allowed sublattice-resolved orbital response exhibits symmetries, imposed by altermagnetism, which lead to a drastic canting of light-induced moments. On the other hand, we find that inclusion of spin-orbit interaction enhances the overall effect drastically, introduces a significant anisotropy with respect to the light polarization and strongly suppresses the canting of induced moments. Remarkably, we observe that the moments induced by linearly-polarized laser pulses in light altermagnets can even exceed in magnitude those predicted for heavy ferromagnets exposed to circularly polarized light. By resorting to microscopic tools we interpret our results in terms of the altermagnetic spin splittings and of their reciprocal space distribution. Based on our findings, we speculate that optical excitations may provide a unique tool to switch and probe the magnetic state of rutile altermagnets.
{"title":"Spin and orbital magnetism by light in rutile altermagnets","authors":"Theodoros Adamantopoulos, Maximilian Merte, Frank Freimuth, Dongwook Go, Lishu Zhang, Marjana Ležaić, Wanxiang Feng, Yugui Yao, Jairo Sinova, Libor Šmejkal, Stefan Blügel, Yuriy Mokrousov","doi":"10.1038/s44306-024-00053-0","DOIUrl":"10.1038/s44306-024-00053-0","url":null,"abstract":"While the understanding of altermagnetism is still at a very early stage, it is expected to play a role in various fields of condensed matter research, for example spintronics, caloritronics and superconductivity. In the field of optical magnetism, it is still unclear to which extent altermagnets as a class can exhibit a distinct behavior. Here we choose RuO2, a prototype metallic altermagnet with a giant spin splitting, and CoF2, an experimentally known insulating altermagnet, to study the light-induced magnetism in rutile altermagnets from first-principles. We demonstrate that in the non-relativisic limit the allowed sublattice-resolved orbital response exhibits symmetries, imposed by altermagnetism, which lead to a drastic canting of light-induced moments. On the other hand, we find that inclusion of spin-orbit interaction enhances the overall effect drastically, introduces a significant anisotropy with respect to the light polarization and strongly suppresses the canting of induced moments. Remarkably, we observe that the moments induced by linearly-polarized laser pulses in light altermagnets can even exceed in magnitude those predicted for heavy ferromagnets exposed to circularly polarized light. By resorting to microscopic tools we interpret our results in terms of the altermagnetic spin splittings and of their reciprocal space distribution. Based on our findings, we speculate that optical excitations may provide a unique tool to switch and probe the magnetic state of rutile altermagnets.","PeriodicalId":501713,"journal":{"name":"npj Spintronics","volume":" ","pages":"1-10"},"PeriodicalIF":0.0,"publicationDate":"2024-09-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.nature.com/articles/s44306-024-00053-0.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142117952","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
The realization and control of exchange bias (EB) are highly desirable for spintronic applications. All-oxide heterostructures comprised of ferromagnetic and antiferromagnetic/multiferroic oxides provide an ideal platform to enable the electric-field control of EB, promising for energy-efficient memory and logic devices. However, the low block temperature (TB) and small bias field (HEB) hinder further advances towards room-temperature applications. Here, we report an alternative approach to enhance the interface-induced EB by using ferrimagnetic double-perovskite with B-site cation ordering. In heterostructures comprised of double-perovskite Sr2FeReO6 (SFRO) and LaFeO3 (LFO), a high TB (about 250 K) and large HEB are observed, which is significantly larger than the counterparts with LFO and ferromagnetic oxides. Further analysis suggests that the cation-ordering and ferrimagnetic spin structure of the double-perovskite could contribute significantly to the enhanced exchanged bias when interfacing with G-type antiferromagnets. Our results open a new avenue for developing all-oxides heterostructures for future magnetic technologies.
在自旋电子应用中，实现和控制交换偏压（EB）是非常理想的。由铁磁性和反铁磁性/多铁氧体组成的全氧化物异质结构为实现 EB 的电场控制提供了一个理想平台，有望用于高能效存储器和逻辑器件。然而，低阻滞温度（TB）和小偏置场（HEB）阻碍了室温应用的进一步发展。在此，我们报告了一种通过使用具有 B 位阳离子有序化的铁磁性双超晶石来增强界面诱导 EB 的替代方法。在由双过氧化物 Sr2FeReO6（SFRO）和 LaFeO3（LFO）组成的异质结构中，我们观察到了高 TB（约 250 K）和大 HEB，这明显大于 LFO 和铁磁氧化物的对应物。进一步的分析表明，当与 G 型反铁磁体相互作用时，双超沸石的阳离子排序和铁磁性自旋结构可能会对增强交换偏压做出重要贡献。我们的研究结果为开发未来磁性技术的全氧化物异质结构开辟了一条新途径。
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