Pub Date : 2025-01-30DOI: 10.1109/LMAG.2025.3536936
Nicholas Homrocky;Cody Trevillian;Vasyl Tyberkevych
Nonreciprocal propagation of surface acoustic waves (SAWs) may be achieved through magneto-elastic coupling with surface spin waves (SSWs). Here, we studied theoretically SAW–SSW coupling in yttrium–iron garnet (YIG)/ gadolinium–gallium garnet (GGG) bilayers magnetized in-plane at an oblique angle to the direction of wave propagation. An expression for the coupling rate that considers actual thickness profiles of both waves has been derived. The effects of the SAW–SSW coupling are most pronounced at the crossing point of the SAW and SSW spectra, which, for typical experimental parameters, occurs at a frequency of about 2 GHz and wavelength 2 µm. Under these conditions, the coupling rate for SSWs localized near the free surface of the YIG layer weakly depends on system parameters and exceeds 25 MHz. In contrast, for the opposite direction of wave propagation, when the SSW is localized near the YIG/GGG interface, the coupling rate rapidly decreases with the increase of YIG thickness, and strong nonreciprocity of the coupling is observed for thicknesses over 0.5 µm. With the increase of YIG thickness above 2.5 µm, coupling of SAW to higher order standing spin waves becomes important, which pollutes the spectrum of hybrid magneto-elastic waves, making observation and practical use of nonreciprocal SAW–SSW coupling more difficult.
{"title":"Magneto-Elastic Coupling of Surface Spin and Surface Acoustic Waves","authors":"Nicholas Homrocky;Cody Trevillian;Vasyl Tyberkevych","doi":"10.1109/LMAG.2025.3536936","DOIUrl":"https://doi.org/10.1109/LMAG.2025.3536936","url":null,"abstract":"Nonreciprocal propagation of surface acoustic waves (SAWs) may be achieved through magneto-elastic coupling with surface spin waves (SSWs). Here, we studied theoretically SAW–SSW coupling in yttrium–iron garnet (YIG)/ gadolinium–gallium garnet (GGG) bilayers magnetized in-plane at an oblique angle to the direction of wave propagation. An expression for the coupling rate that considers actual thickness profiles of both waves has been derived. The effects of the SAW–SSW coupling are most pronounced at the crossing point of the SAW and SSW spectra, which, for typical experimental parameters, occurs at a frequency of about 2 GHz and wavelength 2 µm. Under these conditions, the coupling rate for SSWs localized near the free surface of the YIG layer weakly depends on system parameters and exceeds 25 MHz. In contrast, for the opposite direction of wave propagation, when the SSW is localized near the YIG/GGG interface, the coupling rate rapidly decreases with the increase of YIG thickness, and strong nonreciprocity of the coupling is observed for thicknesses over 0.5 µm. With the increase of YIG thickness above 2.5 µm, coupling of SAW to higher order standing spin waves becomes important, which pollutes the spectrum of hybrid magneto-elastic waves, making observation and practical use of nonreciprocal SAW–SSW coupling more difficult.","PeriodicalId":13040,"journal":{"name":"IEEE Magnetics Letters","volume":"16 ","pages":"1-5"},"PeriodicalIF":1.1,"publicationDate":"2025-01-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143553310","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-01-27DOI: 10.1109/LMAG.2025.3535310
Meng Zhao;Xianfeng Liang;Yuxi Wang;Tao Wu;Jingen Wu;Jinghong Guo;Zhongqiang Hu;Ming Liu
Thin-film magneto-electric composites based on aluminum nitride (AIN) and Sc-doped AlN exhibit great potential for applications in magneto-electric devices. In this letter, we report soft magnetism and microwave properties in FeCoSiB ferromagnetic alloys grown on AlN and AlScN thin films. According to the hysteresis loop, the coercive fields for FeCoSiB/AlN/Mo/Si and FeCoSiB/AlScN/Mo/Si are 43 and 107 Oe, respectively. The influence of interfacial state on magnetic damping is investigated by measuring the magnetic dynamic properties. Scanning electron microscope images show that AlScN film has a larger grain size and rougher surface than that of AlN. The effective magnetization and damping factors are obtained from the ferromagnetic resonance spectroscopy. The damping factor of the magneto-electric heterojunction on AlN/Mo/Si is an order of magnitude higher than that on Si, indicating the interfacial conditions of thin film stacks affect the magnetic dynamic properties. Our findings indicate that the growth quality of piezoelectric materials has a significant impact on magneto-electric films with low-loss tangents at radio-frequency (RF)/microwave frequencies. This work is of practical importance for developing future RF/microwave magneto-electric devices.
{"title":"Soft Magnetism and Microwave Properties of FeCoSiB Ferromagnetic Alloys Grown on AlN and AlScN Thin Films","authors":"Meng Zhao;Xianfeng Liang;Yuxi Wang;Tao Wu;Jingen Wu;Jinghong Guo;Zhongqiang Hu;Ming Liu","doi":"10.1109/LMAG.2025.3535310","DOIUrl":"https://doi.org/10.1109/LMAG.2025.3535310","url":null,"abstract":"Thin-film magneto-electric composites based on aluminum nitride (AIN) and Sc-doped AlN exhibit great potential for applications in magneto-electric devices. In this letter, we report soft magnetism and microwave properties in FeCoSiB ferromagnetic alloys grown on AlN and AlScN thin films. According to the hysteresis loop, the coercive fields for FeCoSiB/AlN/Mo/Si and FeCoSiB/AlScN/Mo/Si are 43 and 107 Oe, respectively. The influence of interfacial state on magnetic damping is investigated by measuring the magnetic dynamic properties. Scanning electron microscope images show that AlScN film has a larger grain size and rougher surface than that of AlN. The effective magnetization and damping factors are obtained from the ferromagnetic resonance spectroscopy. The damping factor of the magneto-electric heterojunction on AlN/Mo/Si is an order of magnitude higher than that on Si, indicating the interfacial conditions of thin film stacks affect the magnetic dynamic properties. Our findings indicate that the growth quality of piezoelectric materials has a significant impact on magneto-electric films with low-loss tangents at radio-frequency (RF)/microwave frequencies. This work is of practical importance for developing future RF/microwave magneto-electric devices.","PeriodicalId":13040,"journal":{"name":"IEEE Magnetics Letters","volume":"16 ","pages":"1-5"},"PeriodicalIF":1.1,"publicationDate":"2025-01-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143489113","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-01-20DOI: 10.1109/LMAG.2025.3531777
Frederik L. Durhuus;Theis H. van Bijlevelt Rix;Maciej A. Głód;Marco Beleggia;Cathrine Frandsen
Understanding thermal relaxation effects in magnetic nanoparticle (MNP) systems is key to several imaging techniques and clinical applications. Here, we consider the Néel relaxation of compact MNP clusters, using Langevin dynamics simulations to compute the relaxation time as a function of magnetostatic coupling strength. By also analyzing individual thermal reversals, we establish connections between the magnetic structure of a cluster and its Néel relaxation time. In particular, faster relaxation and more exotic behavior are observed for 3-D clusters with several nearly degenerate states, as the magnetization intermittently jumps to metastable states, which can facilitate reversal. Conversely, aggregates with many moments in a single flux-closed loop exhibit fewer metastable states and are efficiently blocked by strong dipole coupling.
{"title":"Néel Relaxation of Magnetic Nanoparticle Clusters","authors":"Frederik L. Durhuus;Theis H. van Bijlevelt Rix;Maciej A. Głód;Marco Beleggia;Cathrine Frandsen","doi":"10.1109/LMAG.2025.3531777","DOIUrl":"https://doi.org/10.1109/LMAG.2025.3531777","url":null,"abstract":"Understanding thermal relaxation effects in magnetic nanoparticle (MNP) systems is key to several imaging techniques and clinical applications. Here, we consider the Néel relaxation of compact MNP clusters, using Langevin dynamics simulations to compute the relaxation time as a function of magnetostatic coupling strength. By also analyzing individual thermal reversals, we establish connections between the magnetic structure of a cluster and its Néel relaxation time. In particular, faster relaxation and more exotic behavior are observed for 3-D clusters with several nearly degenerate states, as the magnetization intermittently jumps to metastable states, which can facilitate reversal. Conversely, aggregates with many moments in a single flux-closed loop exhibit fewer metastable states and are efficiently blocked by strong dipole coupling.","PeriodicalId":13040,"journal":{"name":"IEEE Magnetics Letters","volume":"16 ","pages":"1-5"},"PeriodicalIF":1.1,"publicationDate":"2025-01-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143512878","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-11-13DOI: 10.1109/LMAG.2024.3497794
Sheetal Yadav;Monika Sharma;Bijoy K. Kuanr
Magnon–photon hybrid systems have potential applications in quantum information processing. The spatial distribution of magnetic field intensity plays a crucial role in enhancing coupling strength. We have investigated strong magnon–photon coupling using a planar waveguide with defects in the ground for dual-frequency ranging from S to C band. Dual inverted split ring resonators were used as a photon resonator, and a yttrium iron garnet (YIG) pellet acted as a magnon source. The interaction between magnon and photon modes was manipulated by variations in the spatial distribution of the magnetic field along the microstrip line. The ferrite sample was placed at three different positions, viz., A, B, and C. The coupling strength $g$ was tuned from 188 to 281 MHz by varying YIG locations at different positions along the microstrip line. The spin-number-normalized coupling strength was significantly tuned up to 50% by controlling the position of YIG. Hence, it provides another degree of freedom for the qubit information exchange. The other parameters such as cooperativity and coupling constant were also determined. This work paves the way for developing innovative hybrid systems with tunable high-gain magnon–photon coupling systems in planar geometry.
{"title":"Enhancement of Magnon–Photon Coupling Strength: Effect of Spatial Distribution","authors":"Sheetal Yadav;Monika Sharma;Bijoy K. Kuanr","doi":"10.1109/LMAG.2024.3497794","DOIUrl":"https://doi.org/10.1109/LMAG.2024.3497794","url":null,"abstract":"Magnon–photon hybrid systems have potential applications in quantum information processing. The spatial distribution of magnetic field intensity plays a crucial role in enhancing coupling strength. We have investigated strong magnon–photon coupling using a planar waveguide with defects in the ground for dual-frequency ranging from S to C band. Dual inverted split ring resonators were used as a photon resonator, and a yttrium iron garnet (YIG) pellet acted as a magnon source. The interaction between magnon and photon modes was manipulated by variations in the spatial distribution of the magnetic field along the microstrip line. The ferrite sample was placed at three different positions, viz., A, B, and C. The coupling strength \u0000<inline-formula><tex-math>$g$</tex-math></inline-formula>\u0000 was tuned from 188 to 281 MHz by varying YIG locations at different positions along the microstrip line. The spin-number-normalized coupling strength was significantly tuned up to 50% by controlling the position of YIG. Hence, it provides another degree of freedom for the qubit information exchange. The other parameters such as cooperativity and coupling constant were also determined. This work paves the way for developing innovative hybrid systems with tunable high-gain magnon–photon coupling systems in planar geometry.","PeriodicalId":13040,"journal":{"name":"IEEE Magnetics Letters","volume":"15 ","pages":"1-5"},"PeriodicalIF":1.1,"publicationDate":"2024-11-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142938554","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
To address the prevalent issue of vibrations in long boring tools with a significant length-to-diameter ratio, we have developed a novel controllable damping boring tool. This innovative tool leverages the unique properties of magnetorheological elastomers (MREs) to counteract vibrations effectively. Using ANSYS software, we analyzed the magnetic field within the tool, revealing a direct link between excitation current and magnetic induction intensity within the MRE. Concurrently, experiments confirmed a strong correlation between magnetic induction and the MRE's elastic modulus, highlighting the material's tunable stiffness under varying magnetic fields. Further investigation through modal and harmonic response analyses has unveiled that augmenting the MRE's elastic modulus achieves two objectives. First, it raises the natural frequency of the boring tool. Second, and perhaps more importantly, it significantly diminishes the tool's response amplitude to vibrations. To illustrate, at an excitation current of 0 A, our measurements recorded a response amplitude of 0.31504 mm for the controllable damping boring tool. Furthermore, when the excitation current was increased to 1 A, the response amplitude was notably reduced to 0.1523 mm. These compelling results highlight the MRE controllable damping boring tool's exceptional dynamic adjustment capabilities and its remarkable efficacy in vibration suppression.
{"title":"Controllable Damping Boring Tool Based on Magnetorheological Elastomer","authors":"Xuhui Liu;Bin Wan;Bin Xu;Jing Qi;Xingyu He;Zheng Zhou;Yan Wu","doi":"10.1109/LMAG.2024.3490385","DOIUrl":"https://doi.org/10.1109/LMAG.2024.3490385","url":null,"abstract":"To address the prevalent issue of vibrations in long boring tools with a significant length-to-diameter ratio, we have developed a novel controllable damping boring tool. This innovative tool leverages the unique properties of magnetorheological elastomers (MREs) to counteract vibrations effectively. Using ANSYS software, we analyzed the magnetic field within the tool, revealing a direct link between excitation current and magnetic induction intensity within the MRE. Concurrently, experiments confirmed a strong correlation between magnetic induction and the MRE's elastic modulus, highlighting the material's tunable stiffness under varying magnetic fields. Further investigation through modal and harmonic response analyses has unveiled that augmenting the MRE's elastic modulus achieves two objectives. First, it raises the natural frequency of the boring tool. Second, and perhaps more importantly, it significantly diminishes the tool's response amplitude to vibrations. To illustrate, at an excitation current of 0 A, our measurements recorded a response amplitude of 0.31504 mm for the controllable damping boring tool. Furthermore, when the excitation current was increased to 1 A, the response amplitude was notably reduced to 0.1523 mm. These compelling results highlight the MRE controllable damping boring tool's exceptional dynamic adjustment capabilities and its remarkable efficacy in vibration suppression.","PeriodicalId":13040,"journal":{"name":"IEEE Magnetics Letters","volume":"15 ","pages":"1-5"},"PeriodicalIF":1.1,"publicationDate":"2024-11-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142905879","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-10-31DOI: 10.1109/LMAG.2024.3490383
Lei Wang;Chenbing Qu;Rong Zhou;Zhangming Zhu
In this letter, a new differential magnetic field probe with high sensitivity is presented. The differential magnetic probe includes a 180° out-of-phase balun, a pair of differential detection loops, and an output port with a 50 Ω impedance match. Unlike conventional magnetic probes with a single detection loop, a pair of differential detection loops is used to measure double magnetic-field components. Moreover, a 180° out-of-phase balun is utilized to process the differential-mode signals from these differential detection loops, which can make these probes directly connected to the oscilloscope and no longer rely on vector network analyzers. Finally, the differential magnetic probe is designed, simulated, and measured to verify the design effectiveness, and a near-field scanning system is used to characterize the developed probe. Measured results reveal that the designed differential magnetic probe not only can measure more magnetic-field energy, but also directly connect to the oscilloscope due to its own differential mode operation function in the out-of-phase balun. Therefore, the probe is very suitable for actual interference source location testing.
{"title":"A New Differential Magnetic Probe With Out-of-Phase Balun and Differential Loops","authors":"Lei Wang;Chenbing Qu;Rong Zhou;Zhangming Zhu","doi":"10.1109/LMAG.2024.3490383","DOIUrl":"https://doi.org/10.1109/LMAG.2024.3490383","url":null,"abstract":"In this letter, a new differential magnetic field probe with high sensitivity is presented. The differential magnetic probe includes a 180° out-of-phase balun, a pair of differential detection loops, and an output port with a 50 Ω impedance match. Unlike conventional magnetic probes with a single detection loop, a pair of differential detection loops is used to measure double magnetic-field components. Moreover, a 180° out-of-phase balun is utilized to process the differential-mode signals from these differential detection loops, which can make these probes directly connected to the oscilloscope and no longer rely on vector network analyzers. Finally, the differential magnetic probe is designed, simulated, and measured to verify the design effectiveness, and a near-field scanning system is used to characterize the developed probe. Measured results reveal that the designed differential magnetic probe not only can measure more magnetic-field energy, but also directly connect to the oscilloscope due to its own differential mode operation function in the out-of-phase balun. Therefore, the probe is very suitable for actual interference source location testing.","PeriodicalId":13040,"journal":{"name":"IEEE Magnetics Letters","volume":"15 ","pages":"1-5"},"PeriodicalIF":1.1,"publicationDate":"2024-10-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142761395","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-10-31DOI: 10.1109/LMAG.2024.3490380
J. Schmidtpeter;Proloy T. Das;Y. Zabila;C. Schubert;T. Gundrum;T. Wondrak;D. Makarov
Planar Hall magnetoresistive sensors (PHMRs) are promising candidates for various magnetic sensing applications due to their high sensitivity, low power consumption, and compatibility with integrated circuit technology. However, their performance is often limited by inherent noise sources, impacting their resolution and overall sensitivity. Here the effect of three bilayer structures NiFe(10 nm)/IrMn(10 nm), NiFe(30 nm)/IrMn(10 nm), and NiFe(30 nm)/IrMn(20 nm) on noise levels is investigated at low frequency (DC-25 Hz). This study includes a detailed investigation on the optimization process and noise characteristics of multiring PHMR sensors, focusing on identifying and quantifying the dominant noise sources. The experimental measurements are complemented by a theoretical analysis of noise sources including thermal noise, 1/ f noise, intermixing, and environmental noise. The best magnetic resolution is observed for the NiFe(30 nm)/IrMn(10 nm) structure, which achieves a detectivity below 1.5 nT/√Hz at 10 Hz in a nonshielded environment at room temperature. In addition, a substantial improvement in sensitivity is observed by annealing the sensors at 250 °C for 1 h. The findings of this study contribute to a deeper understanding of noise behavior in PHMR sensors, paving the way for developing strategies to improve their performance for demanding sensing applications at low frequencies.
{"title":"Exchange-Biased Multiring Planar Hall Magnetoresistive Sensors With Nanotesla Resolution in Nonshielded Environments","authors":"J. Schmidtpeter;Proloy T. Das;Y. Zabila;C. Schubert;T. Gundrum;T. Wondrak;D. Makarov","doi":"10.1109/LMAG.2024.3490380","DOIUrl":"https://doi.org/10.1109/LMAG.2024.3490380","url":null,"abstract":"Planar Hall magnetoresistive sensors (PHMRs) are promising candidates for various magnetic sensing applications due to their high sensitivity, low power consumption, and compatibility with integrated circuit technology. However, their performance is often limited by inherent noise sources, impacting their resolution and overall sensitivity. Here the effect of three bilayer structures NiFe(10 nm)/IrMn(10 nm), NiFe(30 nm)/IrMn(10 nm), and NiFe(30 nm)/IrMn(20 nm) on noise levels is investigated at low frequency (DC-25 Hz). This study includes a detailed investigation on the optimization process and noise characteristics of multiring PHMR sensors, focusing on identifying and quantifying the dominant noise sources. The experimental measurements are complemented by a theoretical analysis of noise sources including thermal noise, 1/\u0000<italic>f</i>\u0000 noise, intermixing, and environmental noise. The best magnetic resolution is observed for the NiFe(30 nm)/IrMn(10 nm) structure, which achieves a detectivity below 1.5 nT/√Hz at 10 Hz in a nonshielded environment at room temperature. In addition, a substantial improvement in sensitivity is observed by annealing the sensors at 250 °C for 1 h. The findings of this study contribute to a deeper understanding of noise behavior in PHMR sensors, paving the way for developing strategies to improve their performance for demanding sensing applications at low frequencies.","PeriodicalId":13040,"journal":{"name":"IEEE Magnetics Letters","volume":"15 ","pages":"1-5"},"PeriodicalIF":1.1,"publicationDate":"2024-10-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142798050","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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