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J. Z. Shi Y. Yang H. K. Tan S. N. Piramanayagam C. B. Lim H. L. Seet S. L. Ho J. F. Hu 《固体物理学:研究快报》2017,11(2)
Partial crystallization in amorphous magnetic film is observed in this study. The film of Co46Fe46Zr5B3/Ru/Co46Fe46Zr5B3 (CFZB/Ru/CFZB) was prepared on glass substrate by DC magnetron sputtering. The CFZB underlayer (CFZB‐UL) and the CFZB overlayer (CFZB‐OL) were deposited under nominally same sputtering conditions, i.e. target, working gas, working pressure, input power, and deposition duration. The transmission electron microscopy (TEM) images with fast Fourier transform (FFT) patterns revealed that the CFZB‐UL was amorphous while the CFZB‐OL became unexpectedly partially crystallized. The result of X‐ray diffraction (XRD) spectra verified the TEM observation. The cause of the partial crystallization is attributed to the lower concentration of glass formers and the lattice matching between the overlayer and the Ru layer below. 相似文献
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Hongjia Li Dan Wei S. N. Piramanayagam 《Applied Physics A: Materials Science & Processing》2013,112(4):985-991
Magnetic Force Microscopy (MFM) tip coated with perpendicular magnetic anisotropy film (PMA tip) is one of the choices for high resolution imaging at low scan height (SH), since it has negligible tip–sample interaction related to its stable magnetic state, sharp, and small tip stray field. In this work, detailed micromagnetic studies are carried out to understand the effect of geometrical and magnetic parameters including the cone angle θ of the PMA tip, intergrain exchange constant $A_{2}^{*}$ , saturation magnetization M s and uniaxial crystalline anisotropy constant K 1 of the tip coating on the MFM tip resolution. To evaluate the resolution performance of the optimized PMA tip, MFM images of high-density granular recording media and patterned media are simulated. We find that, for the PMA tip and its coating, a cone angle in a range of 36.9° to 53.1°, a saturation M s of 700 emu/cm3, a large uniaxial crystalline anisotropy constant K 1 (>4.9×106 erg/cm3) and a high intergrain exchange constant $A_{2}^{*}$ of (0.3–1.0)×10?6 erg/cm are optimized conditions for high resolution imaging. The optimized PMA tip has an excellent performance on imaging of high-density thin film media (bit size of 8×16 nm2) at low SH of 2–8 nm and bit pattern media with a pitch of 50 nm, edge-edge spacing of 5–15 nm at SH of 8–15 nm. 相似文献
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Hongjia Li Dan Wei S. N. Piramanayagam 《Applied Physics A: Materials Science & Processing》2013,110(1):217-225
The properties of a magnetic force microscopy (MFM) tip are very important for high-resolution magnetic imaging. In this work, micromagnetic models of tips are set up to study the effect of tip-coating microstructure, especially the randomness of anisotropy on tip edge and tip end, on the resolution of MFM. The effective coating height and the resolution potential of tips with various microstructures and magnetic properties have been characterized by investigating the obtained signals from high-density continuous granular thin film disk media with a bit size of 8×16 nm2 and bit-patterned media with a pattern period p of 50 nm. The magnetic moment distribution at the tip end should be perpendicular to the sample to realize a ‘magnetically sharp’ tip, which explains further the improved resolution in the recent experimental reports. Tips with well-controlled grain structure and magnetic anisotropy of coating materials can be applied to both high-density thin film disk media and bit-patterned media. 相似文献
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S.N. Piramanayagam J.Z. ShiH.B. Zhao C.S. MahJ.R Shi J.M. ZhaoJ. Zhang Y.S. Kay 《Journal of magnetism and magnetic materials》2006
Two different approaches to reduce the intermediate layer (IL) thickness in perpendicular recording media are proposed. Such a reduction in IL thickness could lead to improvement in writability and recording performance. The first approach involved the introduction of a magnetic intermediate layer (MIL), to obtain C-axis growth. Media with CoCr alloy layer as the MIL were studied. Reasonably good C-axis growth with a Δθ50 of about 3.8° could be obtained for MIL thickness of about 10 nm. Noise could be controlled by introducing exchange-breaking layers. The other approach involved the use of crystalline soft underlayers (SUL) to obtain suitable growth conditions for the recording layers. For this purpose, CoFeTaCr alloys with a FCC(1 1 1) texture were prepared. A good C-axis dispersion in the recording layer with a Δθ50 of about 3.1° could be obtained for IL thickness of about 5 nm. The present study indicates that the recording medium deposited on crystalline SUL is relatively noisier than that deposited on amorphous SUL. Reducing the noise of the crystalline SUL is a way towards higher areal densities. 相似文献
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Ki Hwan Bae 《中国化学快报》2009,20(11):1321-1323
Phytochemical study on the BuOH-soluble fraction of the stem bark of Populus davidiana resulted in the isolation of a new salicin derivative(1),named davidianoside.The structure was elucidated on the basis of extensive physicochemical and spectroscopic analyses. 相似文献
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From the transport studies in the bilayer manganites LaSr2−x
Ca
x
Mn2O7, we have found the variable-range hopping model proposed by Viret et al to be inadequate to describe the transport of charge in these materials. The polarons appear to hop to their nearest neighbors
with an activation energy, which in part is dependent on the magnetic interactions in the lattice. 相似文献
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K. Srinivasan S.N. Piramanayagam R.W. Chantrell Y.S. Kay 《Journal of magnetism and magnetic materials》2008
Perpendicular magnetic recording media consisting of two stacked CoCrPt–SiO2 recording layers incorporating different O2 content in each layer were studied. The samples used Ru intermediate layers. With increasing O2 levels in the lower recording layer, the samples exhibited marginal change in the crystallographic texture, and superior overall magnetic properties such as higher coercivity and improved exchange decoupling. However, the media grain size remained unchanged. Investigations into the switching mechanism by means of virgin and isothermal remanence magnetization measurements showed the predominance of Stoner–Wohlfarth coherent reversal modes in all samples. The thermal stability dropped slightly. A model that describes the evolution of the microstructure in stacked perpendicular recording media is presented to understand these observations. 相似文献