2015 IEEE Magnetics Conference (INTERMAG)最新文献

{"title":"Stability study of spin torque oscillator for microwave assisted magnetic recording (MAMR)","authors":"T. Zhou, M. Zhang, Z. Yuan","doi":"10.1109/INTMAG.2015.7157098","DOIUrl":"https://doi.org/10.1109/INTMAG.2015.7157098","url":null,"abstract":"MAMR is one of the technologies which could push recording density up to 3-4 Tb/in2 [1-4]. The center part of MAMR is the spin torque oscillator (STO) for the generation of localized ac magnetic field in the microwave frequency regime of 20-30 GHz[5-6]. The STO is placed between the main pole and the trailing shield (Fig. 1a), where a strong magnetic field (gap field) exists. The gap field acts on the STO and greatly affects its performance [7]. Due to very low flying height of 2-3 nm, the STO also senses the field from recording media (Fig. 1a). The media field roughly lies in the magnetization-precession plane of the free layer (field generation layer or FGL) (Fig. 1b), which alters the FGL energy landscape and therefore disturbs its precession, causing STO instability. This is one of the key concerns for MAMR. Using micromagnetic simulation, we studied the STO stability against the gap field and the media stray field. It is found that the Ku of the reference layer, the gap field and the media stray field have a big effect on the STO stability. Possible approaches to enhancing the STO stability are proposed.","PeriodicalId":381832,"journal":{"name":"2015 IEEE Magnetics Conference (INTERMAG)","volume":"18 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2015-05-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"121060915","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":"Harmonic and magnetic charge model comparison of spherical permanent magnet structures considering a neumann boundary","authors":"B. V. Ninhuijs, J. Jansen, B. Gysen, Elena A. Lomonova","doi":"10.1109/INTMAG.2015.7157114","DOIUrl":"https://doi.org/10.1109/INTMAG.2015.7157114","url":null,"abstract":"The rapid advances in assistive devices brought out the desire of spherical actuators because of their multiple degrees of freedom and similarity to ball and socket joints [1]. For this application a high torque density is beneficial for the volume of these devices. Due to the typical structure of slotted spherical actuators, designs have to be modeled in 3-D to gain accurate results. As commercially available modeling tools, such as FEA (finite element analysis), are very time consuming, semi-analytical models are needed to optimize a design. A slotted topology can be evaluated by including a Neumann boundary, representing material with a high permeability and a surface current density sheet distribution to model the coils [2]. Two semi-analytical models exists for obtaining the magnetic flux density generated by a spherical permanent magnet array namely, harmonic model [3] and magnetic charge model [4].","PeriodicalId":381832,"journal":{"name":"2015 IEEE Magnetics Conference (INTERMAG)","volume":"04 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2015-05-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"127258886","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":"A novel analytical model of air-gap permeance in tubular linear switched reluctance actuators with hybrid flux paths","authors":"X. Xue, K. Cheng, Y. Bao, Z. Zhang","doi":"10.1109/INTMAG.2015.7156546","DOIUrl":"https://doi.org/10.1109/INTMAG.2015.7156546","url":null,"abstract":"Due to simple and robust configuration, and without any coils and magnets on movers, a tubular linear switched reluctance actuator (TLSRA) is a promising candidate for applications of frequently reciprocating linear motion, such as linear compressors and automotive active suspension systems. For air-gap in a TLSRA, there are the longitudinal and transverse magnetic paths due to various mover positions. Change in air-gap permeance in a TLSRA results in the thrust force, which drives the mover for linear motion. Thus, the air-gap permeance is the crucial parameter for computing the thrust force in the electromagnetic design and estimating the real-time thrust force in force control of TLSRAs. In general, the air-gap permeance at two special positions can be calculated analytically, such as the maximum and minimum air-gap permeance. It is a challenging issue that an analytically model is developed to compute the air-gap permeance at arbitrary mover positions. This paper focuses on that permeance model development.","PeriodicalId":381832,"journal":{"name":"2015 IEEE Magnetics Conference (INTERMAG)","volume":"2018 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2015-05-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"125182256","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":"Tayloring the hysteresis loop of soft magnetic nanocrystalline alloys by magnetic and tensile stress annealing","authors":"L. Varga","doi":"10.1109/INTMAG.2015.7157083","DOIUrl":"https://doi.org/10.1109/INTMAG.2015.7157083","url":null,"abstract":"The eddy current limits for metallic cores should be shifted above 1 MHz in order to keep the operating frequencies about 100 to 500 kHz for inductors and transformers. The high operating frequency permits the mass and volume reducing which is a major demand nowadays in aerospace and automobile applications. Specially, in the context of aerospace applications, a magnetic material that can maintain a lower core loss over the applicable temperature range can provide a basis for nosing out the competition with ferrites (limited temperature range) and with crystalline permalloy of 17 μm thick (limited plastic yields strength). It has been recognized that for low loss and wide applicable temperature demand magnetic field and stress annealed Finemet represent an advanced material permitting new solutions for high frequency magnetics. Compact toroids without gap can be prepared with high quality factor and high current inductors. This work presents some new results concerning the magnetic field and stress annealing.","PeriodicalId":381832,"journal":{"name":"2015 IEEE Magnetics Conference (INTERMAG)","volume":"15 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2015-05-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"126079010","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":"Magnetocaloric and hysteretic properties of Ni-Mn based Heusler alloys","authors":"T. Gottschall, K. Skokov, E. Palacios, R. Burriel, O. Gutfleisch","doi":"10.1109/INTMAG.2015.7157274","DOIUrl":"https://doi.org/10.1109/INTMAG.2015.7157274","url":null,"abstract":"The aim of this work is the comprehensive characterization of the magnetocaloric effect of Heusler alloys using different measurement techniques like calorimetry, magnetometry and the direct determination of the adiabatic temperature change in order to combine them in the S(T) diagram. It turns out that some discrepancies can appear when comparing measurements obtained with different speeds.","PeriodicalId":381832,"journal":{"name":"2015 IEEE Magnetics Conference (INTERMAG)","volume":"78 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2015-05-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"126166046","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":"Development of high sensitivity multi core MI element","authors":"N. Hamada, A. Shimode, C. Cai, M. Yamamoto","doi":"10.1109/INTMAG.2015.7156660","DOIUrl":"https://doi.org/10.1109/INTMAG.2015.7156660","url":null,"abstract":"MI sensor is a magnetic sensor based on the Magneto Impedance (MI) effect discovered by Mori et al. in 1993[1]. A small and highly sensitive magnetic sensor (AMI 306) based on above MI effect and used as an electromagnetic compass mainly in mobile phones and smart phones has been developed and commercialized by AICHI MICRO INTELLIGENT[2]. According to theoretical analysis, the MI sensor is foreseen to show the fT/√Hz level of noise density[3], and its performance would even be equal to SQUID. MI element (AMI306) with pickup coil fabricated by a plating process is used in electromagnetic compasses. Although it shows magnetic resolution in the micro Tesla order[4], higher performance in sensitivity and noise level is required.","PeriodicalId":381832,"journal":{"name":"2015 IEEE Magnetics Conference (INTERMAG)","volume":"12 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2015-05-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"115066024","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":"Radio-frequency (RF) fly height monitoring system for Heat-Assisted Magnetic Recording (HAMR)","authors":"L. Franca-Neto, B. Knigge, K. Flechsig, K. Hunter","doi":"10.1109/INTMAG.2015.7157660","DOIUrl":"https://doi.org/10.1109/INTMAG.2015.7157660","url":null,"abstract":"In HDDs, during write operation, the transducer head flies over the media with no continuous monitoring on the adequacy of its flying height against sudden incidents. If the head hits an asperity or a lubricant spill drops from the head, the head momentarily oscillates around its intended fly height. This can compromise the data being written. Only by issuing a read command can the drive evaluate the quality of the data just written. This verification after write is not normally performed because it impacts drive performance. Heat-Assisted Magnetic Recording (HAMR) holds promises for higher data densities in magnetic media into the future and an “always-on” fly height monitoring system is desired. In HAMR, maintaining adequate fly height during write operation is a requirement from both the magnetic writing and the near-field heating antenna operation. The Radio-Frequency (RF) based system described in this work for fly height monitoring is non-magnetic in nature and, since the gap between head and media is smaller than the mean distance between air molecules, this system is also immune to temperature changes in the head or in the ambient. As shown in figure 1, the air gap between the flying head and the media is represented in electrical domain by capacitors (C1 and C2 in fig. 1). An RF signal of frequency significantly above the frequencies taken by the data signal's spectrum (cf. fig. 1) is injected onto the write lines. This RF signal capacitively couples onto all the elements on the head and the head-media interface (cf. fig. 1). When the head changes its fly height, the corresponding capacitance for the air gap changes its value. This varying capacitance behaves as a charge pump, which amplitude modulates (AM) the RF signal and injects this AM-modulated RF signal back into the head wiring. This signal travels back through the suspension and is detected at the pre-amplifier end. The amplitude of the sidebands carry information on fly height changes. The closer the head flies to the media, the stronger the AM sideband tones for the same disturbance in fly height.","PeriodicalId":381832,"journal":{"name":"2015 IEEE Magnetics Conference (INTERMAG)","volume":"7 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2015-05-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"115179298","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":"Preparation of Fe-based soft magnetic composites with high Bs by acidic bluing coating","authors":"G. Zhao, C. Wu, M. Yan","doi":"10.1109/INTMAG.2015.7157714","DOIUrl":"https://doi.org/10.1109/INTMAG.2015.7157714","url":null,"abstract":"Fe-based soft magnetic composites (SMCs) are technologically important due to their unique properties such as satisfactory magnetic performance and low loss for high frequency applications. Insulation coating of the ferromagnetic powders is critical in the preparation of SMCs. While traditional phosphate treatment allows surface passivation of the Fe powders, the obtained phosphate coating layers are non-magnetic, resulting in decreased saturation magnetization. Consequently, it is essential to develop SMCs with both high flux density and low loss. In this work, acidic bluing method has been used to grow Fe3O4 layers as insulation coating on the surfaces of iron powders. As Fe3O4 is a ferromagnetic material with high electrical resistivity, the effect of magnetic dilution can be avoided.","PeriodicalId":381832,"journal":{"name":"2015 IEEE Magnetics Conference (INTERMAG)","volume":"1 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2015-05-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"115489621","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":"Effect of air-gap between metal strips and a ferrite plate on magnetic shielding","authors":"H. Park, J. Kwon, S. Kwak, S. Ahn","doi":"10.1109/INTMAG.2015.7157202","DOIUrl":"https://doi.org/10.1109/INTMAG.2015.7157202","url":null,"abstract":"In this paper, the effect of air-gap between the metal strip and ferrite plate on magnetic shielding in the presence of a periodic line current source is analyzed in two-dimensional and approximate model of the WPT coils in electric vehicles and mobile devices. An analytical method based on Fourier transform and mode matching technique is proposed to investigate the penetration of quasistatic magnetic field into the ferrite plate and metal strips.","PeriodicalId":381832,"journal":{"name":"2015 IEEE Magnetics Conference (INTERMAG)","volume":"33 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2015-05-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"116060919","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":"Analytical expressions for transition width and transition jitter in granular PMR media taking account of switching field distribution","authors":"T. Jin, H. Muraoka, S. Greaves","doi":"10.1109/INTMAG.2015.7157321","DOIUrl":"https://doi.org/10.1109/INTMAG.2015.7157321","url":null,"abstract":"We have reported analytical expressions for transition width and transition jitter based on the media micro-structure and the readback resolution. In most practical applications, the switching field distribution (SFD) cannot be ignored. In this work we derive analytical formulations that are good approximations for the transition width and transition jitter using Voronoi cell modeling with a finite SFD.","PeriodicalId":381832,"journal":{"name":"2015 IEEE Magnetics Conference (INTERMAG)","volume":"990 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2015-05-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"116227978","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}