Fabrication of Co-Pt Dot Array with 1 Tdot/in2 for Bit Patterned Media by Low Energy Ion Etching

祐治, 近藤; 隆, 千葉; 順, 有明; 香, 田口; 基寛, 鈴木; 直己, 河村; Mohamad, Zurina; 純男, 保坂; 崇, 長谷川; 俊二, 石尾; 直樹, 本多

doi:10.3379/msjmag.1006r003

Cited by 5 publications

(2 citation statements)

References 10 publications

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“…This capability has been used to directly evaluate the magnetic properties of bit-patterned media. 167,168,[171][172][173] Bit-patterned media 174) was proposed as a new scheme for recording information on magnetic media with ultra-high density data storage. Recording on isolated magnetic dots of perpendicular anisotropy would greatly improve the thermal stability and could reduce the reading noise compared to the continuous granular media presently in practical use.…”

Section: Micro Xmcd Magnetometry In Bit-patterned Mediamentioning

confidence: 99%

“…2 ), 172) to verify the controllability of the magnetic switching field widths by introducing the inter-dot exchange coupling, and to determine the intrinsic contribution to the switching field width caused by the distribution of structural and magnetic properties of each dot. 173) In 2011, the XMCD microprobe at SPring-8 BL39XU was upgraded with the reduction in the focused beam size to 100 nm.…”

Section: Micro Xmcd Magnetometry In Bit-patterned Mediamentioning

confidence: 99%

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Recent Progress of the X-ray Magnetic Circular Dichroism Technique for Element-Specific Magnetic Analysis

Nakamura

Suzuki

2013

J. Phys. Soc. Jpn.

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Recent trend of the X-ray magnetic circular dichroism (XMCD) spectroscopy-based technique and the related scientific topics at SPring-8 are reviewed. At the third-generation synchrotron radiation facility, the key developments in the XMCD technique include i) significant improvements in the accuracy and sensitivity of XMCD measurements with a quick helicity switching of circularly polarized X-rays, ii) introduction of extreme conditions (strong pulsed magnetic field and high pressures), and iii) new experimental setup using the high-brilliance X-ray source (microfocusing, reflection geometry, and high-pressure cells). These achievements have effectively extended the capability of the XMCD technique, a unique magnetic probe with an element-specificity, providing fundamental scientific insights in spintronics and magnetic recording devices, magnetic nanoparticles, and magnetism under high-magnetic field and high pressures.KEYWORDS: X-ray magnetic circular dichroism, element specific magnetic hysteresis, synchrotron radiation X-rays Historical ReviewElement-specific magnetic measurements are widely recognized as a powerful experimental technique for the study of magnetic materials and have previously been exploited mainly by Mössbauer spectroscopy. For the last 30 years, an energy-tunable and polarized X-ray source at synchrotron radiation facilities has given rather expansive possibilities of element-specific magnetic measurements using X-ray spectroscopy. Indeed, X-ray magnetic circular dichroism (XMCD) spectroscopy 1,2) has become one of the leading techniques for element-specific magnetic measurement using a resonant effect in the core-shell absorption with circularly polarized X-ray photons.The XMCD effect was first observed at the Fe K edge in the hard-X-ray region in 1987 by Schütz et al.3) In their experiment, an XMCD spectrum of pure iron was obtained by reversing the direction of magnetic fields applied to a sample, and the circularly polarized X-rays were provided by the off-orbital radiation from a bending magnet (off-plane method).3) The recorded XMCD signal was quite small, of the order of ÁI=I $ 5 Â 10 À3 . Subsequently, XMCD spectra at the L 2;3 edges of rare-earth elements [4][5][6] and at the L 2;3 edges of 5d metals in some alloys with 3d transition metals were also reported. 7) XMCD measurements over a wide energy range that is similar to the extended X-ray absorption fine structure (EXAFS), called magnetic EXAFS, in Fe and Gd 3 Fe 5 O 12 showed a capability of analyses of local magnetic structures using dichroic effects. 8,9) In the soft-X-ray region, the first XMCD spectrum at the Ni L 2;3 edges in a Ni single crystal was reported by Chen et al. in 1990. 10) The circularly polarized soft X-rays were obtained by the off-plain method, similar to the previous XMCD measurement at the Fe K edge.3) The intensity of the observed XMCD signal was about 8% with respect to the resonant absorption, the so called white line, and was much larger than that recorded at the K edge. The strong XMCD value at the...

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Section: Micro Xmcd Magnetometry In Bit-patterned Mediamentioning

confidence: 99%

Section: Micro Xmcd Magnetometry In Bit-patterned Mediamentioning

confidence: 99%

Recent Progress of the X-ray Magnetic Circular Dichroism Technique for Element-Specific Magnetic Analysis

Nakamura

Suzuki

2013

J. Phys. Soc. Jpn.

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Investigation on the origin of switching field width in Co-Pt dot array

et al. 2011

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Direct measurement of single-dot coercivity and statistical analysis of switching field distribution in bit-patterned media using scanning hard-X-ray nanoprobe

Suzuki

Ariake

2016

Journal of Applied Physics

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To investigate the possible sources of the switching field distribution in bit-patterned media, we applied a scanning hard-X-ray nanoprobe technique based on X-ray magnetic circular dichroism spectroscopy to an array of Co-Pt dots with the typical diameters of 200 nm. Element-specific magnetization curves at the Pt L3 edge were measured for individual dots isolated from each other, and the magnetization switching field (coercivity) values were determined for more than 100 individual dots. To assess the effect of dot diameters as a possible source of switching field distribution, a statistical analysis of the coercivity values and dot diameters measured for many dots was performed. The resulting switching field distribution had a mean of ⟨HSW⟩=1.80 kOe and a standard deviation of σHSW = 0.64 kOe. The relative deviation of σHSW/⟨HSW⟩=36% was not in good agreement with the relative dispersion in a dot diameter of σD/⟨D⟩=2.7%, and no clear correlation between the coercivity and dot diameter was observed. These results may suggest other possible sources of switching field distribution than dot diameter, such as dispersion in the c-axis orientation and in magnetocrystalline anisotropy.

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Fabrication of Co-Pt Dot Array with 1 Tdot/in2 for Bit Patterned Media by Low Energy Ion Etching

Cited by 5 publications

References 10 publications

Recent Progress of the X-ray Magnetic Circular Dichroism Technique for Element-Specific Magnetic Analysis

Recent Progress of the X-ray Magnetic Circular Dichroism Technique for Element-Specific Magnetic Analysis

Investigation on the origin of switching field width in Co-Pt dot array

Direct measurement of single-dot coercivity and statistical analysis of switching field distribution in bit-patterned media using scanning hard-X-ray nanoprobe

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