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Article type: Cover
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Published: October 08, 2009
Released on J-STAGE: September 20, 2017
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Article type: Index
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Published: October 08, 2009
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Yukio NOZAKI, Naoyuki NARITA, Terumitsu TANAKA, Kimihide MATSUYAMA
Article type: Article
Session ID: MMS2009-55
Published: October 08, 2009
Released on J-STAGE: September 20, 2017
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Microwave-assisted magnetic recording (MAMR) in perpendicularly magnetized Co/Pd multilayer was experimentally investigated using microwave magnetic fields generated by micro-fabricated coplanar waveguide. Broadening or splitting of the peak profile in the FMR spectrum suggesting the formation of multidomain structure appears after the microwave field is applied. The dominance of microwave-assisted nucleation of magnetization is supported by the frequency dependence of the probability with which the multidomain structure appears.
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Takashi KOMINE, Hiroshi MURAKAMI, Ryuji SUGITA
Article type: Article
Session ID: MMS2009-57
Published: October 08, 2009
Released on J-STAGE: September 20, 2017
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In this study, the influence of the pulse current waveform on the domain wall motion in a magnetic nanowire with notch was investigated by using micromagnetic simulation. As a result, it was found that domain wall depinning was enhanced by an adequate pulse current frequency, which was slightly lower than the natural frequency estimated by gravity point of domain wall. The presence of notch in nanowire, the difference of pinning potential for domain wall in each side causes the different oscillation in each domain wall and the coupled oscillation. The critical current density was estimated varying the duty ratio of the pulse current. The critical current with a pulse of a duty ratio of about 0.5 was most effectively decreased.
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Ayumu KATO, Naoyuki NARITA, Kenji NODA, Terumitsu TANAKA, Yukio NOZAKI ...
Article type: Article
Session ID: MMS2009-58
Published: October 08, 2009
Released on J-STAGE: September 20, 2017
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Energy assisted recording technology is considered to be employed in order to realize ultra high density magnetic recording over Tera-bits/inch^2. Microwave assisted recording which is one of the energy assisted recording, was focused in this study, and magnetization reversals for recording media was simulated using micromagnetic simulator. Recorded track width was found to increase with increase in microwave frequency, and region of the magnetization reversal enhanced by microwave field was also found to shift depending on magnetization rotation direction of spin torque oscillator and head field direction during signal recording process.
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Naoyuki NARITA, Terumitsu TANAKA, Yukio NOZAKI, Kimihide MATSUYAMA
Article type: Article
Session ID: MMS2009-59
Published: October 08, 2009
Released on J-STAGE: September 20, 2017
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Microwave assisted magnetic reversal behavior for single exchange coupled nano-pillar was analyzed considering exchange coupled composite media using micromagnetic simulator. In the case that the thickness of the soft magnetic layer is substantially thinner than exchange length, the magnetization behaviors for soft and hard layers are almost uniform because of the strong exchange coupling between hard magnetic layer and thin soft magnetic layer. On the other hand, magnetization behaviors dominated by the soft and the hard magnetic layers were found at low and high frequency region for the ECC pillar when the thickness of soft magnetic layer is close to exchange length. Microwave frequency and microwave field strength required for magnetization reversal were also found to be lower and smaller than those for hard magnetic layer only.
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Kenjiro Fujimoto, Takahiro KAWANO, Atsushi ONOE, Masahiro TAMURA, Masa ...
Article type: Article
Session ID: MMS2009-60
Published: October 08, 2009
Released on J-STAGE: September 20, 2017
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We demonstrate very-high-density ferroelectric recording experiments of 1Tbit/in^2 in polycrystalline Pb (Zr, Ti)O_3 (PZT) thin film for the first time. A high-quality polycrystalline PZT thin film was successfully deposited on a silicon substrate with a SrRuO_3 (SRO) electrode by metal-organic chemical vapor deposition (MOCVD) technique. The roughness of the PZT film was reduced to less than 1nm by chemical mechanical polishing (CMP) method. The PZT film has a very high controllability for domain inversion. Our fabrication process also enables high productivity. Therefore, our PZT film has potential to be a mass-productive ferroelectric recording medium for high-density storage systems.
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Yoshitaka SASAGO, Masaharu KINOSHITA, Takahiro MORIKAWA, Kenzo KUROTSU ...
Article type: Article
Session ID: MMS2009-61
Published: October 08, 2009
Released on J-STAGE: September 20, 2017
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We have fabricated the cross-point phase change memory with a selection diode made of poly-Si. The selection diode was fabricated using a low-thermal-budget process that achieved low contact resistivity, high on-current density of 8MA/cm^2 and low off-current density of 100A/cm^2. The improvement in the properties of poly-Si diode makes the set/reset operation of the cross-point 4F^2 cell possible, leading to the size reduction of phase change memory chip.
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Kazuya JIMBO, Naoya SAITO, Shigeki NAKAGAWA
Article type: Article
Session ID: MMS2009-62
Published: October 08, 2009
Released on J-STAGE: September 20, 2017
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A Stress Assisted Magnetization Reversal (SAMR) method has been demonstrated in order to reduce a power consumption during magnetization reversal process in a perpendicular magenetoresistive random access memory. In this study, a giant magnetoresistive multilayer of Cu(15nm)/Terfenol-D(10nm)/Cu(3nm)/TbFeCo(30nm)/Cu(15nm) were prepared. By using both of an upper and a bottom antioxide layers of the Cu, the multilayer kept its perpendicular magnetization after baked at 100℃ for 2 minutes. Perpendicular component of magnetization reversal in the GMR multilayer were observed during SAMR process by anomalous Hall effect. As a result, the magnetization of a free layer is shifted from perpendicular to in-plane under a stress application of 279MPa.
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Naoaki Miyamoto, Hideto Ohmori, Shigeki Nakagawa
Article type: Article
Session ID: MMS2009-63
Published: October 08, 2009
Released on J-STAGE: September 20, 2017
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Magnetic-coupling between TbFeCo and FeCo in perpendicular MTJ with RE-TM alloy films was investigated. Two specimens that have different crystalline orientation of FeCo were prepared; one is TbFeCo/FeCo(001)/Ta and the other is TbFeCo/FeCo(110)/Ta, and magnetic properties were observed. As a result, it was confirmed that squareness ratio of the specimens with FeCo(001) was about 9% higher than that of the specimens with FeCo(110). In addition, lattice constants of FeCo(001) films were observed, and it was confirmed that FeCo lattices were needed to be stretched along perpendicular direction in order to obtain appropriate squareness in perpendicular magnetic properties.
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Article type: Appendix
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Published: October 08, 2009
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Article type: Appendix
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Published: October 08, 2009
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Article type: Appendix
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Published: October 08, 2009
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