{"title":"Decomposition of Magnetic Field Intensity in Ferrite Based on Time Derivative of Magnetic Flux Density and Power Loss","authors":"H. Saotome, T. Washizu","doi":"10.3379/msjmag.2007r004","DOIUrl":"https://doi.org/10.3379/msjmag.2007r004","url":null,"abstract":"","PeriodicalId":36791,"journal":{"name":"Journal of the Magnetics Society of Japan","volume":"14 1","pages":"102-107"},"PeriodicalIF":0.0,"publicationDate":"2020-07-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"87628849","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"Iron Losses and Magnetic-Hysteresis Properties Under GaN Inverter Excitation at High-Frequencies","authors":"A. Yao, R. Moriyama, T. Hatakeyama","doi":"10.3379/msjmag.2007l002","DOIUrl":"https://doi.org/10.3379/msjmag.2007l002","url":null,"abstract":"","PeriodicalId":36791,"journal":{"name":"Journal of the Magnetics Society of Japan","volume":"34 1","pages":"87-90"},"PeriodicalIF":0.0,"publicationDate":"2020-07-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"72510975","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
D. Oyama, Y. Adachi, M. Miyamoto, N. Ono, A. Imamura, D. Watanabe
We experimentally revealed that a direct current (DC) biased excitation method can reduce the noise in parallel fluxgate magnetometers composed of a permalloy ring core. The noise suppression was achieved by decreasing the Barkhausen noise and increasing the open-loop sensitivity using the nonlinearity of the B-H curve with the DC-biased excitation. The noise performance depends on the excitation parameters: frequency, amplitude, and DC-bias. We proposed that the parameters should be determined based on the evaluation of the sensitivity and noise level in both open-loop and closed-loop modes. Specifically, a contour map of the closed-loop noise is useful for understanding the noise decrease with different values of the amplitude and DC-bias. We also demonstrated the effectiveness of the DC-biased excitation method using a commercially available fluxgate magnetometer (APS520A, Applied Physics Systems). Using the DC-biased excitation method, the noise level was approximately one-fourth compared to that of the original electronics.
{"title":"Noise Suppression in Parallel Fluxgate Magnetometers by DC-Biased Excitation Method","authors":"D. Oyama, Y. Adachi, M. Miyamoto, N. Ono, A. Imamura, D. Watanabe","doi":"10.3379/msjmag.2005r006","DOIUrl":"https://doi.org/10.3379/msjmag.2005r006","url":null,"abstract":"We experimentally revealed that a direct current (DC) biased excitation method can reduce the noise in parallel fluxgate magnetometers composed of a permalloy ring core. The noise suppression was achieved by decreasing the Barkhausen noise and increasing the open-loop sensitivity using the nonlinearity of the B-H curve with the DC-biased excitation. The noise performance depends on the excitation parameters: frequency, amplitude, and DC-bias. We proposed that the parameters should be determined based on the evaluation of the sensitivity and noise level in both open-loop and closed-loop modes. Specifically, a contour map of the closed-loop noise is useful for understanding the noise decrease with different values of the amplitude and DC-bias. We also demonstrated the effectiveness of the DC-biased excitation method using a commercially available fluxgate magnetometer (APS520A, Applied Physics Systems). Using the DC-biased excitation method, the noise level was approximately one-fourth compared to that of the original electronics.","PeriodicalId":36791,"journal":{"name":"Journal of the Magnetics Society of Japan","volume":"45 47","pages":"79-86"},"PeriodicalIF":0.0,"publicationDate":"2020-05-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"72390704","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
The nitrogen insertion and topotactic extraction (NITE) method was used to explore an unknown metastable phase of an FeNi alloy with an Fe:Ni ratio of 1:1. We found that partly ordered non-equilibrium L1 2 -FeNi can be obtained through Fe 2 Ni 2 N as the intermediate nitride phase. The experimental results of both x-ray diffraction and transmission electron microscopy with energy dispersive x-ray spectrometry are consistent in identifying the denitrided material as L1 2 -FeNi. Ni atoms preferentially occupy the corner sites in an estimated 96% of cases. No significant difference was found in the magnetization curves between the precursor of A1-FeNi and L1 2 -FeNi particles. Our results suggest that the NITE method is not only a useful way for synthesizing fully ordered alloys of equilibrium phases such as L1 0 -FeNi but also for creating metastable phases like L1 2 -FeNi.
{"title":"Synthesis of L12-FeNi Nanoparticles by Nitrogen Insertion and Topotactic Extraction Method","authors":"G. Sho, H. Kura, H. Yanagihara","doi":"10.3379/msjmag.2005r005","DOIUrl":"https://doi.org/10.3379/msjmag.2005r005","url":null,"abstract":"The nitrogen insertion and topotactic extraction (NITE) method was used to explore an unknown metastable phase of an FeNi alloy with an Fe:Ni ratio of 1:1. We found that partly ordered non-equilibrium L1 2 -FeNi can be obtained through Fe 2 Ni 2 N as the intermediate nitride phase. The experimental results of both x-ray diffraction and transmission electron microscopy with energy dispersive x-ray spectrometry are consistent in identifying the denitrided material as L1 2 -FeNi. Ni atoms preferentially occupy the corner sites in an estimated 96% of cases. No significant difference was found in the magnetization curves between the precursor of A1-FeNi and L1 2 -FeNi particles. Our results suggest that the NITE method is not only a useful way for synthesizing fully ordered alloys of equilibrium phases such as L1 0 -FeNi but also for creating metastable phases like L1 2 -FeNi.","PeriodicalId":36791,"journal":{"name":"Journal of the Magnetics Society of Japan","volume":"14 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2020-05-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"91146746","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
N. Yasuda, S. Kittaka, Y. Kono, T. Sakakibara, K. Kakizaki, K. Kamishima
We investigated the synthesis conditions and magnetic properties of M-Ti substituted Ba 12 Fe 28 Ti 15 O 84 with initial compositions of Ba 12 Fe 28-2x Ti 15+x M x O 84 (M = Zn, Mg, Ni, Cu, and Co) sintered at 1100-1300°C. The highest substitution amounts of M-Ti for Fe were consistent with the Ti-ion preference of each transition metal site reported before, suggesting that substituted Ti ions also preferred the sites with high Ti-ion occupancies. The spontaneous magnetizations and Curie temperatures were decreased as the substitution amount x was increased, which means that the substitution weakened the super-exchange interactions between Fe-O-Fe. The highest Zn-Ti substitution rate was lower than the other M-Ti substitution rates, which implies that Zn ions tend to enter specific M(2) and M(14) sites in Ba 12 Fe 28 Ti 15 O 84 . The sweep of the magnetic field from 0 to 80 kOe changed the relative dielectric constant of Ba 12 Fe 28 Ti 15 O 84 by 0.283%. This variation of the dielectric constant caused by the application of magnetic fields is not negligible, showing that this compound should be categorized as a multiferroic material.
研究了在1100 ~ 1300℃烧结的初始成分为Ba 12fe 28-2x Ti 15+x M x O 84 (M = Zn, Mg, Ni, Cu, Co)的M-Ti取代Ba 12fe 28 Ti 15o 84的合成条件和磁性能。M-Ti对Fe的最高取代量与之前报道的每个过渡金属位点的Ti-离子偏好一致，表明取代的Ti离子也倾向于具有高Ti占位的位点。随着取代量x的增加，Fe-O-Fe的自发磁化强度和居里温度降低，表明取代削弱了Fe-O-Fe之间的超交换作用。最高的Zn-Ti取代率低于其他M-Ti取代率，说明Zn离子倾向于进入Ba 12 Fe 28 Ti 15 O 84中特定的M(2)和M(14)位点。在0 ~ 80 kOe磁场范围内，Ba 12fe 28ti 15o84的相对介电常数改变了0.283%。这种由磁场作用引起的介电常数的变化是不可忽略的，表明这种化合物应归类为多铁性材料。
{"title":"Synthesis and Magnetic Properties of M2+Ti4+ Substituted Ba12Fe28Ti15O84","authors":"N. Yasuda, S. Kittaka, Y. Kono, T. Sakakibara, K. Kakizaki, K. Kamishima","doi":"10.3379/msjmag.2005r004","DOIUrl":"https://doi.org/10.3379/msjmag.2005r004","url":null,"abstract":"We investigated the synthesis conditions and magnetic properties of M-Ti substituted Ba 12 Fe 28 Ti 15 O 84 with initial compositions of Ba 12 Fe 28-2x Ti 15+x M x O 84 (M = Zn, Mg, Ni, Cu, and Co) sintered at 1100-1300°C. The highest substitution amounts of M-Ti for Fe were consistent with the Ti-ion preference of each transition metal site reported before, suggesting that substituted Ti ions also preferred the sites with high Ti-ion occupancies. The spontaneous magnetizations and Curie temperatures were decreased as the substitution amount x was increased, which means that the substitution weakened the super-exchange interactions between Fe-O-Fe. The highest Zn-Ti substitution rate was lower than the other M-Ti substitution rates, which implies that Zn ions tend to enter specific M(2) and M(14) sites in Ba 12 Fe 28 Ti 15 O 84 . The sweep of the magnetic field from 0 to 80 kOe changed the relative dielectric constant of Ba 12 Fe 28 Ti 15 O 84 by 0.283%. This variation of the dielectric constant caused by the application of magnetic fields is not negligible, showing that this compound should be categorized as a multiferroic material.","PeriodicalId":36791,"journal":{"name":"Journal of the Magnetics Society of Japan","volume":"83 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2020-05-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"79988016","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
This paper discusses the iron loss and magnetic hysteresis properties of a ring core of nanocrystalline magnetic materials (NMM) at room temperature (RT) and high temperature (HT) under pulse-width-modulation (PWM) inverter excitation. As in the case of the DC hysteresis loop, the coercivity of the NMM ring core at 300 ◦ C (HT) under PWM inverter excitation is larger than that at RT, mainly because of weakening of intergranular magnetic coupling at HT. In addition, in the NMM ring core, the area of the minor loops at HT increases compared with that at RT. Iron loss in the NMM core fed by the PWM inverter increases in tandem with an increase in temperature. Hysteresis loss increases dramatically in tandem with an increase in temperature for every tested case. In a low carrier frequency region, the eddy current loss at 300 ◦ C increases.
{"title":"Iron Loss and Magnetic Hysteresis Properties of Nanocrystalline Ring Core at High and Room Temperatures Under Inverter Excitation","authors":"A. Yao, R. Moriyama, T. Hatakeyama","doi":"10.3379/msjmag.2005l001","DOIUrl":"https://doi.org/10.3379/msjmag.2005l001","url":null,"abstract":"This paper discusses the iron loss and magnetic hysteresis properties of a ring core of nanocrystalline magnetic materials (NMM) at room temperature (RT) and high temperature (HT) under pulse-width-modulation (PWM) inverter excitation. As in the case of the DC hysteresis loop, the coercivity of the NMM ring core at 300 ◦ C (HT) under PWM inverter excitation is larger than that at RT, mainly because of weakening of intergranular magnetic coupling at HT. In addition, in the NMM ring core, the area of the minor loops at HT increases compared with that at RT. Iron loss in the NMM core fed by the PWM inverter increases in tandem with an increase in temperature. Hysteresis loss increases dramatically in tandem with an increase in temperature for every tested case. In a low carrier frequency region, the eddy current loss at 300 ◦ C increases.","PeriodicalId":36791,"journal":{"name":"Journal of the Magnetics Society of Japan","volume":"160 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2020-05-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"73648035","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
In an effort to increase the maximum energy product ((BH)max) and coercivity (HcJ) of Zn-bonded Sm−Fe−N magnets, we developed a process for preparing Sm−Fe−N and Zn powders with low oxygen contents and subjected them to spark plasma sintering. The oxygen content, remanence, and coercivity of the Sm−Fe−N powder were 0.22 wt%, 151 A·m2·kg−1, and 0.72 MA·m−1, respectively. The oxygen content and secondary average particle size of the Zn powder were 0.083 wt% and 0.93 μm, respectively. The magnetic properties of the Zn-free Sm−Fe−N magnets included an HcJ of 0.86 MA·m−1 and a (BH)max of 188 kJ·m−3, while the Zn-bonded (10 wt%) Sm−Fe−N magnets exhibited excellent magnetic properties with a (BH)max of 200 kJ·m−3 and an HcJ of 1.28 MA·m−1. Compared with previous studies, this is the high (BH)max observed for a Sm−Fe−N bulk magnet simultaneously displaying a high HcJ. The (BH)max of the Zn-bonded magnets was greater than that of the Zn-free magnets owing to the higher relative density of the former. Therefore, Zn is an effective binder for increasing not only the coercivity but also the density of Sm−Fe−N magnets. Consequently, the procedure reported herein permits the successful preparation of high-performance Sm−Fe−N bulk magnets.
为了提高Zn键合Sm - Fe - N磁体的最大能量积(BH)max)和矫顽力(HcJ)，我们开发了一种制备低氧含量Sm - Fe - N和Zn粉末的工艺，并对其进行火花等离子烧结。Sm - Fe - N粉末的氧含量、剩余物和矫顽力分别为0.22 wt%、151 A·m2·kg - 1和0.72 MA·m - 1。锌粉的氧含量为0.083 wt%，二次平均粒度为0.93 μm。无锌Sm - Fe - N磁体的HcJ值为0.86 MA·m−1,HcJ值为188 kJ·m−3，而含锌(10 wt%) Sm - Fe - N磁体的HcJ值为1.28 MA·m−1,HcJ值为200 kJ·m−3。与以前的研究相比，这是Sm - Fe - N体磁铁同时显示高HcJ的高(BH)max。由于锌结合磁体的相对密度较高，其(BH)max大于无锌磁体。因此，Zn是一种有效的粘结剂，不仅可以提高Sm - Fe - N磁体的矫顽力，还可以提高磁体的密度。因此，本文报道的方法允许成功制备高性能Sm−Fe−N块体磁体。
{"title":"Preparation of Sm−Fe−N Bulk Magnets with High Maximum Energy Products","authors":"R. Matsunami, M. Matsuura, N. Tezuka, S. Sugimoto","doi":"10.3379/msjmag.2005r003","DOIUrl":"https://doi.org/10.3379/msjmag.2005r003","url":null,"abstract":"In an effort to increase the maximum energy product ((BH)max) and coercivity (HcJ) of Zn-bonded Sm−Fe−N magnets, we developed a process for preparing Sm−Fe−N and Zn powders with low oxygen contents and subjected them to spark plasma sintering. The oxygen content, remanence, and coercivity of the Sm−Fe−N powder were 0.22 wt%, 151 A·m2·kg−1, and 0.72 MA·m−1, respectively. The oxygen content and secondary average particle size of the Zn powder were 0.083 wt% and 0.93 μm, respectively. The magnetic properties of the Zn-free Sm−Fe−N magnets included an HcJ of 0.86 MA·m−1 and a (BH)max of 188 kJ·m−3, while the Zn-bonded (10 wt%) Sm−Fe−N magnets exhibited excellent magnetic properties with a (BH)max of 200 kJ·m−3 and an HcJ of 1.28 MA·m−1. Compared with previous studies, this is the high (BH)max observed for a Sm−Fe−N bulk magnet simultaneously displaying a high HcJ. The (BH)max of the Zn-bonded magnets was greater than that of the Zn-free magnets owing to the higher relative density of the former. Therefore, Zn is an effective binder for increasing not only the coercivity but also the density of Sm−Fe−N magnets. Consequently, the procedure reported herein permits the successful preparation of high-performance Sm−Fe−N bulk magnets.","PeriodicalId":36791,"journal":{"name":"Journal of the Magnetics Society of Japan","volume":"9 1","pages":"64-69"},"PeriodicalIF":0.0,"publicationDate":"2020-05-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"84493244","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2020-05-01DOI: 10.3379/msjmag.2005rv002
M. Ishikawa, Y. Saito, K. Hamaya
In this paper, we introduce the current status of research and development on silicon-based spin metal-oxidesemiconductor field-effect transistors (Si spin-MOSFETs) in terms of electrical spin injection, spin transport, and spin detection in Si-based lateral spin-valve devices. First, it is important for understanding the spin transport in Si to obtain reliably large spin signals for analyses. By using n+-Si spin-transport layers with a small cross-sectional area of ~0.3 μm2, we can observe 50-fold the magnitude of four-terminal nonlocal (NL) magnetoresistance signals and NL Hanle signals at room temperature in previous works. Next, by analyzing these spin signals, we can reliably estimate the spin diffusion length and spin relaxation time of n+-Si at room temperature. Also, we clarify that inter-valley spinflip scattering is one of the dominant spin relaxation mechanisms in n+-Si at room temperature. Furthermore, we find the crystal orientation effect on spin injection/detection efficiency in n+-Si and discuss the possible origins. Finally, we demonstrate a room-temperature MR ratio of 0.06%, twice as large as that in the previous work.
{"title":"Study of Spin Transport and Magnetoresistance Effect in Silicon-based Lateral Spin Devices for Spin-MOSFET Applications","authors":"M. Ishikawa, Y. Saito, K. Hamaya","doi":"10.3379/msjmag.2005rv002","DOIUrl":"https://doi.org/10.3379/msjmag.2005rv002","url":null,"abstract":"In this paper, we introduce the current status of research and development on silicon-based spin metal-oxidesemiconductor field-effect transistors (Si spin-MOSFETs) in terms of electrical spin injection, spin transport, and spin detection in Si-based lateral spin-valve devices. First, it is important for understanding the spin transport in Si to obtain reliably large spin signals for analyses. By using n+-Si spin-transport layers with a small cross-sectional area of ~0.3 μm2, we can observe 50-fold the magnitude of four-terminal nonlocal (NL) magnetoresistance signals and NL Hanle signals at room temperature in previous works. Next, by analyzing these spin signals, we can reliably estimate the spin diffusion length and spin relaxation time of n+-Si at room temperature. Also, we clarify that inter-valley spinflip scattering is one of the dominant spin relaxation mechanisms in n+-Si at room temperature. Furthermore, we find the crystal orientation effect on spin injection/detection efficiency in n+-Si and discuss the possible origins. Finally, we demonstrate a room-temperature MR ratio of 0.06%, twice as large as that in the previous work.","PeriodicalId":36791,"journal":{"name":"Journal of the Magnetics Society of Japan","volume":"5 1","pages":"56-63"},"PeriodicalIF":0.0,"publicationDate":"2020-05-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"88214982","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"Study on Asymmetric Magnetic Pole Structure for IPM Motor Using Neodymium Bonded Magnet","authors":"T. Yanagisawa, Y. Yoshida, K. Tajima","doi":"10.3379/msjmag.2003r005","DOIUrl":"https://doi.org/10.3379/msjmag.2003r005","url":null,"abstract":"","PeriodicalId":36791,"journal":{"name":"Journal of the Magnetics Society of Japan","volume":"19 1","pages":"45-51"},"PeriodicalIF":0.0,"publicationDate":"2020-03-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"74988324","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"Information Stability in Three-Dimensional Heat-Assisted Magnetic Recording","authors":"T. Kobayashi, Y. Nakatani, Y. Fujiwara","doi":"10.3379/msjmag.2003r003","DOIUrl":"https://doi.org/10.3379/msjmag.2003r003","url":null,"abstract":"","PeriodicalId":36791,"journal":{"name":"Journal of the Magnetics Society of Japan","volume":"1 1","pages":"34-39"},"PeriodicalIF":0.0,"publicationDate":"2020-03-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"84733814","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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