IEEE International Magnetics Conference最新文献

{"title":"Intrinsic magnetic properties of Sm/sub 2/Fe/sub 17-x/M/sub x/N/sub y//C/sub y/ [M=Al, Ga, or Si]","authors":"M. Kubiś, D. Eckert, A. Handstein, B. Gebel, K. Muller, L. Schultz","doi":"10.1109/INTMAG.1999.837860","DOIUrl":"https://doi.org/10.1109/INTMAG.1999.837860","url":null,"abstract":"The partial substitution of Fe by AI, Ga or Si enhances the thermal stability of the interstitial Sm,Fe,,-carbides making possible the application of high temperature processes for the preparation of highly dense magnets [l-4]. The intrinsic magnetic properties of the compounds investigated in the present work play an important role for the assessment of their potential for possible applications. SmzFe,,.,M, samples with M = Al (x = I, 2, 31, M = Ga (x = 0.5, 1, 2), and M = Si (x = 0.25,0.5, I ) were prepared by arc melting, induction melting and homogenization treatment. The samples were pulverized by crushing and milling to mean particle sizes mainly below 10 pm and nitrogenated at 500OC for 6hrs in 800mbar N, or carhurized at 500°C for 16hrs in 600 mbar CH,. Alternatively, a melt-carburized Sm,Fe15Ga2C,.B sample was prepared. The powders were aligned in a magnetic field of 2 T, cold compacted with a pressure of about 500MPa and resin-bonded. The Curie temperatures were obtained fmm M’(T)-Plots of thermomagnetic measurements. Demagnetization curves were measured in a vibrating sample magnetometer. The saturation polarization I, and the anisotropy field Ha were determined by a numerical fining procedure of the demagnetization curves in the region of the reversible rotation magnetization processes [5]. The obtained values of Curie temperatures, saturation polarizations and anisotropy fields for the Sm2Fe,,.,M,N,/C, samples are given in Fig. I . For comparison, the intrinsic magnetic properties of Sm,Fe,,N,/C, taken from ref. [6] were added to the graphs. Curie temperature and saturation polari2ation decrease monotonically for increasing content of substitution M. The nonmagnetic dilution by the substitution atoms seems to be the dominating effect. The nitrides exhibit always larger values than the corresponding carbides. The drop of the saturation polarization 1, is very strong. For example. J, of Sm2Fe,,GazC, is only 0.81 T and with that much lower than the reported value of 1.05 T for melt-carburized Sm2Fe,,Ga2C, [2]. On the other hand, the I,-value of 1.0 T obtained for the melt-carburized Sm,Fe,,Ga2C18 sample corresponds very well with ref. [2]. It can he concluded, that the gas-carburization has an unfavourable effect on the saturation polarization compared to melt-carburization. The anisotropy fields increase significantly for small M contents x 4 1 (e.g. Sm,Fe165Ga, 5CyR”y with Ha = 25.0126.6 T compared to Ha = 16122 T for Sm,Fe,,CylN,). For M contents x 2 1 the anisotropy fields start to decrease. The decrease of H, for the carbides is weaker than that for the nitrides, leading finally to comparahle or even higher Ha values for ‘the carbides (e.g. Sm,Fe,,AI,C/”, with Ha= 17.3115.2 T). The gas-carburized SmzFe,,Ga,C, sample shows a much higher H,value (17.8 T) than the melt-carburized Sm2FelrGa2CiR y n p l e (Ha= 10.1 T, which corresponds well with the reported Ha-value for melt-carburized Sm2Fe,,GazC2 of 13 T [2]). In this case, a favoura","PeriodicalId":425017,"journal":{"name":"IEEE International Magnetics Conference","volume":"115 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1999-05-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"116589596","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":"The effect of concentration and valency of iron sulphate media on the bio-magnetic iron sulphides produced through continuous culture","authors":"A. Bahaj","doi":"10.1109/INTMAG.1999.837700","DOIUrl":"https://doi.org/10.1109/INTMAG.1999.837700","url":null,"abstract":"Biologically produced iron sulphide (FeS) is of great interest in the area of bioremedation as it posses adsorbing properties surpassing those produced by chemical means. This paper reports on the effect of varying the relative concentrations of Fe(II) and Fe(III) sulphates in the culture medium of a sulphate reducing bacteria chemostat on the magnetic properties of the iron sulphide produced. An optimum Fe(II):Fe(III) ratio is determined to maximise the magnetic susceptibility of the microbial sulphide produced. This will result in a reduction of the magnetic field intensity used in magnetically separating heavy metals in hioremediation applications. The paper details the economics of the separation and proposes a magnetically and cost optimised process for such applications.","PeriodicalId":425017,"journal":{"name":"IEEE International Magnetics Conference","volume":"14 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1999-05-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"128651478","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":"Magnetoelastic waves in ferri- and antiferromagnetic crystals near spin reorientaional phase transission","authors":"I. Dikshtein, Sung-Ho S. Salk","doi":"10.1109/INTMAG.1999.837950","DOIUrl":"https://doi.org/10.1109/INTMAG.1999.837950","url":null,"abstract":"Anomalous decrease of the sound velocity and the important role that nonlinear processes play near the spin-reorientational phase transitions (OPT) in the limited ferrimagnetic (FM) and antifemmagnetic (AF) crystals make such o~ystals promising materials for use in electronic devices [I]. The e5ciency of such devices can be raised considerably by using surface waves, since the energy of such waves is concenmted within a thin surface layer. The study of the spectra of magnetoelasic (ME) waves in limited specimens of FM and AF makes it possible to determine the type of sofl mode involved in OPT. It is usually assumed that the h e energy depends only fiom the symmetric part of the distortion tensor, u,,=aU/& i.e. on the strain tensor ek=(aU/3xk+aU&,)I2, where U is a displacement vector. However, within this approach the h e energy is invariant with respect to translation of the volume elements of the crystal, but it is not invariant with respeci to a local rotation of such elements. When sound propagates in magnetic material, the volume elements of the medium hun locally together with the magnetic anisotropy axes, which increases the cnergy of the crystal. Examining this problem in a rigorous setting requires building a consistent translationand rotation-invariant theory that should also allow for the dependence of energy on the antisymetric pan of the distortion tensor r~y=(aU&~-aUJ&,)I2 related to the rotation of small volume elements with nspect to each other upon an inhomogeneous deformation of the crystal [2]. In this case the presence of a magnetic field endows thin plates with a mmsvetse rigidity and leads to transformation of the dispersion law of a flexural wave into a linear (sonic) law 131. Here we use a rigorous rotationand translation-invariant theory to study the Lamb and Raylei& waves propagation near an OPT induced by temperature in orthorhombic AF and FM bounded by planes-l, and placed in a magnetic field HIlx. For example, the dispersion laws for the Rayleigh, flexural and transverse Lamb waves with NIX in a plate of an easy-plane AF with weak ferromagnetism and low magnetic anisotropy in a basal plane xy (H&<HAz) are given by","PeriodicalId":425017,"journal":{"name":"IEEE International Magnetics Conference","volume":"1 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1999-05-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"128680374","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":"Multiresolution algorithm for integral and boundary element equations in magnetic field computations","authors":"J.C. Yang, K. Shao, H. Yu, J. Lavers","doi":"10.1109/INTMAG.1999.837673","DOIUrl":"https://doi.org/10.1109/INTMAG.1999.837673","url":null,"abstract":"Wavelet algorithm far integral equations was first studied in [I] . In magwetic field computations, previously plblished p a p utilized the standard scheme to gel a dense ma& and then applied the fast wavelet vansfonii to appvimate it to a sparse one. Therefore, one have to allccate extra metnon for the transformed matrix. Mnmver, the t r d d mabix did not appear to have beuer condition number lhan the original one. In this paper, we use wavelet functions as bath basis functions and weight funnions. It is a reasonable trade-olf between tbe entire domain and subsstiM basis functions. The whole dornais may be divided iiib several subsections, while in each subsection the higher resolution basis is incorporated, whsch preserve the merits of entire domain basis functions. A sparse matrix thus is derived","PeriodicalId":425017,"journal":{"name":"IEEE International Magnetics Conference","volume":"21 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1999-05-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"129897714","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":"The calculation of magnetostatic wave devices amplitude- and phase-frequency characteristics by partial wave beams method","authors":"V. Shcheglov, V. Zubkov","doi":"10.1109/INTMAG.1999.837215","DOIUrl":"https://doi.org/10.1109/INTMAG.1999.837215","url":null,"abstract":"","PeriodicalId":425017,"journal":{"name":"IEEE International Magnetics Conference","volume":"04 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1999-05-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"130536143","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":"Modeling and experimental investigation of thermal interaction in the head-disk interface of mr head based recording systems","authors":"Qingfang Leng, Bo Liu, Gongye Zhou, Wei Zhang, A. Mydeen, T. Yamamoto","doi":"10.1109/INTMAG.1999.837107","DOIUrl":"https://doi.org/10.1109/INTMAG.1999.837107","url":null,"abstract":"I Intmduetion The read-back signal thermally induced from the head-disk interface is one of the most serious concern in the engineering integration of the MR head based rewrding systems. especially when technology moves to sub-micro-inch beaddisk spacing and 40 Gb/in2 mal densities [l][2]. This paper presents the results of thermal signal modehng, beating and cooling process simulation, and experimental analysis. An analytical model is proposed which takes the headdisk spacing into account and can be used for quantitative analysis of the head-disk systems. Results of the transient process study show that a submicron lateral resolution c m be achieved for characterizing the disk surface. Experimental inveslipations, supported by the analytical model, indicate thhd the air thermal conductivity inside the laser bump hole is smaller than that of outside the bump hole. Satisfyiog agreement between estimated bump shape and the bump shape measured by AFM is achieved when proper thermal conductiviv ratio is used. Experimental results also suggest that the MR thermal signal can be used for in-situ monitoring of the headdisk spacing variation, with the relationship provided by the proposed analytical model.","PeriodicalId":425017,"journal":{"name":"IEEE International Magnetics Conference","volume":"26 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1999-05-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"123972724","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":"The permeability of ferrite plated films","authors":"P. J. van der Zaag, P. Lubitz, Y. Kitamoto, M. Abe","doi":"10.1109/INTMAG.1999.837745","DOIUrl":"https://doi.org/10.1109/INTMAG.1999.837745","url":null,"abstract":"Recently, there has been a growing interest in the fabrication of ferrite films, especially by pulsed laser deposition (PLD), e.g [I], but also by sputtering, see for instance [Z]. Owing to their insulating character ferrite films could be applied for integrated inductors 111 or to improve the efficiency of thin film recording heads 131. Most of the studies of the growth of ferrite films, thus far, only report the saturation magnetization value, Ms, or the coercivity, He. However, in mast applicatons the permeability of the ferrite films is the key parameter, which unfortunately is rarely reported [2]. A disadvantage of the films grown by PLD or sputtering is that they require a high deposition temperature of typically around 650 'C, which is too high for most application in devices which involve other thin layers. Ferrite films grown by ferrite plating offer a much more favourable depostion temperature of only 80 'C [4]. We will discuss the characterization of the magnetic properties, notably permeability's of NiZn-ferrite plated films. The approx. 1 pm thick NiZn-ferrite films studied had a Ms % 520 kA/m which is comparable to bulk values for NiZn-ferrite. As can be seen from Fig. 1, the NiZn-ferrite films grown by ferrite plating on a glass substrate have a p = 28 f 3 (open balls). This value can be increased to p= 60 *5 hy an anneal step at T 2 325 OC, which in addition increases","PeriodicalId":425017,"journal":{"name":"IEEE International Magnetics Conference","volume":"40 1-8 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1999-05-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"123379441","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":"45/spl deg/ torque method for containing anisotropy constant","authors":"Y. Uesaka, Y. Nakatani, N. Hayashi, H. Fukushima, N. Inaba","doi":"10.1109/INTMAG.1999.837498","DOIUrl":"https://doi.org/10.1109/INTMAG.1999.837498","url":null,"abstract":"","PeriodicalId":425017,"journal":{"name":"IEEE International Magnetics Conference","volume":"31 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1999-05-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"123452556","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":"Design opmization of a moving magnet disk drive actuator with minimized detrimental electromagnetic forces","authors":"S.X. Chen, Y. Mah, Q. Li, H. Lin","doi":"10.1109/INTMAG.1999.837615","DOIUrl":"https://doi.org/10.1109/INTMAG.1999.837615","url":null,"abstract":"Introduction Advances in map ti^ recording head and media over the last decade hate pushed recording rlen,tiy up io a poml uhcre funher improvement i s Itkcl) to hc impeded h) mechanical constrainti l'mently. the WYO bandwidth of most cnnvcnlional head positioning ,)stem i s lirmtcd by thr In-plane rcronance modes of the actuator mechanism For a typrcal 3 5-inch drive actuator, the lowest t n p l ~ ~ monance. referred a.. the QR mode (quai-rigid body mude). (X'CUIS between 3 10 5 MIL. This IS due to the ela5ticity of the pirot h n g and Ibe mass of the moving pans of the actuator Moi l IlDD today UVP a moiinp voicciod inutur IO drive he actuatnr arm carrying the readlwnte heads. Howcvcr. the driving lurcc produced b) the conventional moving voice coil motor has a large tn.planc component In the seek direction. This creates rubstanual reaction furcc at thr pivot k m n g which cm pnlcnually cxcitcs the QR mode of the actuator Ihe Q K made, i f exited. causes undesirable vibration of the arm in the data track acehng diwcuun. Thir csuccs difficulty in head positioning Juring mck following and l irmta the bandwidth of the servo system T h i r paper prrscnls a novel moving -et dctyillor which substantially solres the abow described d i s h a n t a g , and provides w improve actuator mechamism for high density recording rn hard disk dnves","PeriodicalId":425017,"journal":{"name":"IEEE International Magnetics Conference","volume":"101 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1999-05-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"123621134","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 remote query glucose dosimeter based -on magnetostatic coupling","authors":"Y. Liu, C. Tong, P. Stoyanov, K. Loiselle, C. Grimes","doi":"10.1109/INTMAG.1999.837359","DOIUrl":"https://doi.org/10.1109/INTMAG.1999.837359","url":null,"abstract":"Magnetically soft tbin film elements, see Figure 1, are bonded to a polymer layer that is made to swell in response to glucose concentration. The dosimeter design consists of four triangles, initidly spaced 50 )un apart, arranged tn form a 12 mm x 12 mm square with the triangle tips centered at a common origin. As the polymer size changes so does the distance between the magnetic elements and hence tbe magnetic domain structure per magnetostatic coupling. The sensor is placed within a lime varying magnetic field of an intensity sufficient to switch the magnetization vector of the collective magnetic elements comprising the dosimeter. The magnetic flux changes generated by the periodic magnetization reversals can be detected as a series of voltage spikes in suitably lofated detecting coils. Concentration levels of the chemical anal@ can be related to the ampliok of the d e w voltage spike that the time varying flux generates [l]. Figure 2 shows the voltage spike amplitude as afunction of element spacing for tbe 'split square' design shown in Fig. I ; window pane smctures have also been used with success. The sensing principle is general and can be adapted to sense a variety of analytes by appropriate polymer design. Since the sensor is monitored through changes in magneoc flux no physical connections are needed to obtain sensor information.","PeriodicalId":425017,"journal":{"name":"IEEE International Magnetics Conference","volume":"9 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1999-05-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"123640011","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}