IEEE International Magnetics Conference最新文献

{"title":"High pressure gas-solid interstitial modification of Nd(Fe,M)/sub 12/ (M=Ti,V,Mo) with H and N atoms","authors":"P. Oleinek, A. Handstein, O. Gutfleisch, K. Muller, L. Schultz, I. R. Harris","doi":"10.1109/INTMAG.1999.837417","DOIUrl":"https://doi.org/10.1109/INTMAG.1999.837417","url":null,"abstract":"Since the discovery of the improvement of magnetic properties in interstitially modified rare earth @)transition metal (T) compounds [I], many studies have been performed to investigate the nitrogenation behavior of R-T compounds with ThMnlrtype structure [2, 31. However, the mechanisms involved are not yet completely understood and different nitrogen absorption behaviors and stability ranges have been observed for different substitutions [4]. We studied the hydrogenation and nitrogenation behavior of NdFellTi, NdFelonVl,z5 and NdFelasMo1.5 at room temperature starting pressures between 1 bar and 30 bar by differential scanning calorimetry @SC) and x-ray diffraction (XRD). The hydrogenation behavior is an important parameter for the HDDR process and was also studied by temperature pressure analysis (TPA). Fig. 1 shows DSC traces of a NdFelo.JMol,5 powder sample (particle size < ISpm) heated up to 740T with 5 Wmin in a pure nitrogen atmosphere. At 1 bar starting pressure, one dominant exothermic peak is observed at 4WC, which, according to the results of XRD, can be attributed to the interstitial modification. A smaller peak at a temperature of 664°C indicates the decomposition reanion of the NdFelo.5Mol sNY phase with ThMn12-type structure into a mixture of a-Fe and an amorphous phase. When the starting pressure is raised to 5 bar, the fust peak shifts to a temperature of 449OC, and the second exothermic peak becomes more important, now appearing at €&Soc. Both peaks appear at even lower temperatures if the pressure IS further increased to 10 bar and 30 bar. Fig. 2 shows the XRD diagrams of the samples after the DSC run Fig. Za shows the pattern of the parent compound. High scattering intensities result from a-Fe and an amorphous phase when the N2 gas pressure in the DSC is 1 bar, but the decomposition reaction is incomplete and a residue of the ThMnlz-type structure is left (b). No intensities orighting fiom NdN were found When the N2gas pressure is raised, the decomposition reaction into a-Fe and an amorphous phase becomes complete (c-e). In both compounds NdFellTi and N~F~Io.RVI,ZS, the decomposition reaction of the ThMno-type structure into a-Fe and an amorphous phase also o c w s , but at slsnificantly lower temperatures (551°C and 607°C at I bar and 527T and 567°C at 30 bar, respectively). Additionaly, in these compounds the decomposition reaction is complete at a pressure of 1 bar. The interstitial modification and the decomposition reaction are irreversible in the case of N. For H, both reactions are reversible. Mer the hydrogen induced disproportionation process, a recombination of the ThMnn-type structure was successfully performed. Fig. 3 shows the number of H atoms per formula unit during a heat treatment in HZ atmosphere at a pressure of 1 bar for the three alloys under ipvestigation. The increase above 600T indicates the disproportionation process. In the case of NdFeloJMols this reaction is not completed at 86OOC. The reported resu","PeriodicalId":425017,"journal":{"name":"IEEE International Magnetics Conference","volume":"105 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":"121553381","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":"Tribological characteristics of SiNx film","authors":"Jianming Wen, Xiao Ying, King Wong, G. Barth, Ga-Lane Chen","doi":"10.1109/INTMAG.1999.837115","DOIUrl":"https://doi.org/10.1109/INTMAG.1999.837115","url":null,"abstract":"In order to meet the ever i n c r d data storage demanding wide range approaches have been taken such asto i n c r e a s e d density ;md to explore new technology. Magneto-optical (MO) technology coupled with flying head has received increaxd attention recently. A set of new tribological questions needs to be answered in order to have a better understanding of the whole new interfa . In MO media, a thick dielectric layer in a tri-or ad-laver-sbucture is nonnallv","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":"122536999","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":"Some aspects of nucleation upon defects in crystals of the ferrite-garnet type","authors":"R. Vakhitov, A. R. Yumaguzin","doi":"10.1109/INTMAG.1999.837787","DOIUrl":"https://doi.org/10.1109/INTMAG.1999.837787","url":null,"abstract":"","PeriodicalId":425017,"journal":{"name":"IEEE International Magnetics Conference","volume":"59 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":"122907695","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":"Thermal stability of magnetization in perpendicular thin film media","authors":"M. Futamoto, Y. Hirayama, N. Inaba, Y. Honda, K. Ito, A. Kikugawa, T. Takeuchi","doi":"10.1109/INTMAG.1999.837098","DOIUrl":"https://doi.org/10.1109/INTMAG.1999.837098","url":null,"abstract":"Inbodnetion The anal densim of hard disk drives mav exceed ZOGWid arnirnd the yew 2000. The future nCOrdi i~~iediu i '~ & & d i i G a t h G e F & & g l i y G i G iduoed Ai&c-cryitaliine size and magnetic exchangedecoupled s l ~ ~ c t u r e . However. the decrease in gram size increascs the effect of thermal fluctuation[lJ. Perpendicular recording has a high potential for the application to very high areal density magnetic recording. sin= we can employ a thicker recording layer than with the longitudinal recording. Furthermore, the demagnctlzation working between the adjacent recording bils decreases with increasing !he linear recording density. These baric propcrlico are desirable in keeping the thermal stability of w r d e d information especially at high areal densities. Lo this paper, we report on the lhcnnal decay charactetis!ics of perpendicular media and discuss on their future possibilities. Results and DLsrussion We have developed the COCI-alloy pcrpcndicular media with high squmness (Mr/Mu0.95). moderate coercivities (Hc:2.4kOe) and low noise charactcristico[2.3]. The recording and the signal dccay characteristics are compared with those of CoCr Pl longitudinal media with dfferenl thicknesses(20, 16. Sum). The normalized roll-off curyes %oE that the recording resolution is 2€-30% higher with the perpendicular media(thiclmcss-2Snm). The medium SIN at 300kFCI is in the order: CaCrPt(L,Rnrn) > CoCrTa(P.2Snm) or CoCrPt(L,lbnm) > CoCrPt(L,Xnm) > CoCrPt(P.25nm). Here L and P denote longitudinal and perpendicular, respectively. The recorded signal decay characteristics measured at m m temperature for 40 and 400 kFCI recordings arc wmpared in Fig. 1. At 400 kFCI, the longitudinal media showed more than lO%/l@ s. o l signal dmp when the rewrding layer was thinner than I6nm. On L e conwry. the CoCrh perpendicular medium with the high MrlMs showed little signal &cay for all linear dcnrilies. I t is possible lo suppress he demagnetization of perpendicular recording at low h e a r dcnsilm hy employing the high squareness media[2.4,51. With increasing the linear density. the demagnetization becomes weaker with perpeudicular recording mode and the ourput signals at high density rccordmg (Fig.2) showed almost DO signal decay. We have also to lake mto acwuut of the efTect of almosphenc temperahre on signal deca) characteristic[61. The dccay rate of longitudinal recordmg is reponed to be enhanced at higher temperatures more than that expected from a proportional scaling with tempcrature[7l. Thermal stability is discussed based on the KuV/kT value of magnetic swilchmg unit which can be regarded as a crystalline grain core in low noise medtm[8.9], though a careful attention should be payed in delennming the Ku value for polycrystalline magnetic lhin filmr[lOl. Table I shows the Ku values caperimentally determined using the well defmed smgle crystal magneuc thin filmsll I] . 'Ihe Ku values decrease more than 20% by increasing the tempcrature from 290 to 400K","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":"125311932","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":"Interface effects on the magnetisation and magnetooptical rotation in Co/sub x/Ni/sub 1-x//Pt multilayers","authors":"M. Seddat, H. Lassri, M. Tessier, R. Krishnan, M. Nývlt, Š. Višňovský","doi":"10.1109/INTMAG.1999.837864","DOIUrl":"https://doi.org/10.1109/INTMAG.1999.837864","url":null,"abstract":"","PeriodicalId":425017,"journal":{"name":"IEEE International Magnetics Conference","volume":"45 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":"125697301","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":"Controlling of sub-/spl mu/m domain in spin valve strip with conductor current","authors":"K. Matsuyama, H. Hosokawa, Y. Nozaki","doi":"10.1109/INTMAG.1999.837966","DOIUrl":"https://doi.org/10.1109/INTMAG.1999.837966","url":null,"abstract":"","PeriodicalId":425017,"journal":{"name":"IEEE International Magnetics Conference","volume":"22 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":"129818720","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":"Large air gap coupler for inductive charger","authors":"H. Sakamoto, K. Harada, S. Washimiya, K. Takehara, Y. Matsuo, F. Nakao","doi":"10.1109/INTMAG.1999.837225","DOIUrl":"https://doi.org/10.1109/INTMAG.1999.837225","url":null,"abstract":"A novel magnetic coupler with large air gap is presented. It is developed for the electric vehicle's automatic inductive charger. The new inductive coupler proposed here has sufficient exciting inductance even if it has a large air gap. Calculated exciting inductance is 40 {micro}H at 2 turns of winding and 5 mm air gap, which agrees well with measured value. In order to assess the generation of heat caused by the eddy current, the magnetic flux densities in the inductive charger and also a flat iron plate, to which the inductive charger is attached, are calculated. The conversion efficiency with the coupler and a MOSFETs full-bridge inverter of 100 kHz, is 97% at 8.3 kW output.","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":"129673956","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":"Thermal stability and reliability of spin-valve films with synthetic antiferromagnet exchange-biased by IrMn","authors":"H. Fuke, K. Saito, M. Yoshikawa, K. Koui, H. Iwasaki, M. Sahashi","doi":"10.1109/INTMAG.1999.837317","DOIUrl":"https://doi.org/10.1109/INTMAG.1999.837317","url":null,"abstract":"ANTlFERROMAGNETANGE-BIASED BY IrMn H. N. Fukc, K. Saito, M. Yoshikawa, K. Koui, H. Iwasaki and M. Sahashi Materials and Devices Research Laboratories, Research and Development Center, Toshiba Corporation, 72, Horikawa-cho, Saiwai-ku, Kawasaki 210, Japan Jntroduction An antiferromagnetic layer that plays an most impnrlant role in spin-valve has been investigated in order to obtain high thermal stability and reliability for use or spin-valve GMR heads in giga bits density magnetic recording lJ,z). We reported that Ir,Mn, exchange-coupled to CoFe shows a T, of 270% and is suitable for a narrow gap head structure that is nccdcd in order to realize more high density recording as IrMn shaws high H,, at lhinnrr layer thicknrss than ordered antiferromagnetic films as NiMn and PtMn\". However, other papers have reporled poor IrMn properties with a T. ofbelow 250'C \",\". In this study. we report the relation ktwccn lrMn crystal gram and good lrMn propertics and thc thermal stability of spin-valves with a synthetic antiferromagnet ( S y w exchange-biased by the IrMn layer. -E.&.I ' Im We believe that large KnFV is important to obtain high T. (Here, Ks is the crystal anisotropy 01 the antiferromagnetic film, and V i s the volume of the crystal grain. Namely. it is needed to make the grain size of lrMn layer grow in order lo obtain high Tw On the other hand, it was reported for CrAl antiferomagntic layer that H, is in proportion to l l D by using Malozemolf random field approximation on the assumplion that L=D ?.(Here, L is the coupling arei, and D is the grain size.) As the critical thickness for CrAl is thick, it is necessary to assume d-nD (n: cocilicienl) for lrMn with thin critical thickness. If these models are suitable, it is thought that T. increases when the grain size of IrMn layer grows lager, while H,,,dccrcascs. Figure 1 shows the grain six of lrMn layer dcpcndencc for H , , and T,. The grain size was calculatcd by using Schcrrur'a cquation from IrMn (111) XRD peak. The grain sizes were ahout equal to the lrMn layer thickness. I t was found lhal T, increases as the grain size of lrMn layer increases, while H, .decreases, and an H,, of 4WOe at R.T. and a T, o1300'C for CoFc(2nm)llrMn (10nm) spin-valves were obtained. Thermal stahilitv and reliahilitv of SvAFIlrMn spin-wilvcs The spin-valve (S.V.) film wilh a SyAF exchange-biased by the IrMn layer with high T, and high H, TalNiFelCoFelCulCoFe~ulC~~Fellr?,Mn,,(l0nm)~a, was prupared on alumina coalcd Si substrates hy DC sputtering. The IOW oxygen contcnl lrMn largcl was uscd. The lilms were annealed at 270'C for 1 -10 hours under a magnetic licld olmore Ihan 7kOe. Figure 2 shows the thermal stability fnr a reversed magnetic ticld n l 10kOe IO the pinncd layer direction. At uach temperature, it was annealed f<>r 10 minutes under the rcvcrscd m;ignclic licld. The H,.,' was defined as shown in fig.3. The pinned direction was stable ti l l about I X W C . And Ihc pinncd direction gradually changed to Ihc r","PeriodicalId":425017,"journal":{"name":"IEEE International Magnetics Conference","volume":"15 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":"129375353","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":"Nonequiljbrium in As-deposited Mn ferrite thin films by RF sputtering","authors":"T. Tanaka","doi":"10.1109/INTMAG.1999.837435","DOIUrl":"https://doi.org/10.1109/INTMAG.1999.837435","url":null,"abstract":"","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":"129565093","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 new method for fast motion-capturing in three dimensional space using a global linear-gradient and two uniform magnetic fields","authors":"I. Sasada, H. Morimoto","doi":"10.1109/INTMAG.1999.837365","DOIUrl":"https://doi.org/10.1109/INTMAG.1999.837365","url":null,"abstract":"In this paper, a new method for fast motion-capturing in three dimensional space is proposed. This method employs triaxial magnetometers and three magnetic fields spanned over the space of interest: two uniform magnetic fields, the one perpendicular to the other, and a linear gradient magnetic field generated by a pair of head-on magnetic dipoles. Interesting point of the third magnetic field is that well-defined linear-gradient distributions occur in three orthogonal directions, one of which direction is along the line connecting the two dipoles. Hence. once the orientiuion of the magnetometer is determined with two uniform magnetic fields, its position relative to the symmetrical center of the linear-gradient fields can be uniquely determined based on a linear relationship between the field skngth and the position of the third magnetic field.","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":"130130004","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}