Magnetic structures in CoCr media for perpendicular magnetic recording

Abstract.Ferromagnetic Ni-Cr and Co-Cr alloy thin films were electrodeposited from aqueous solution containing trivalent chromium (Cr 3+ ) ions and glycine. According to the Tafel slopes obtained from the cathode polarization curves for Ni-Cr and Co-Cr alloy deposition, it was estimated that Cr 3+ ions inhibited Ni 2+ and Co 2+ ions from electrodepositing. Ni and Co preferentially electrodeposited rather than Cr and the electrodeposition process of Ni-Cr and Co-Cr was categorized to "normal co-deposition type." At the cathode potential of -1.8 V vs.Ag/AgCl/KCl sat., Ni-9.5%Cr and Co-8.4%Cr alloy deposits were obtained. X-ray diffraction patterns of the electrodeposits revealed that pure Ni and pure Co consist of large crystal grains, while Ni-9.5%Cr and Co-8.4%Cr alloys were composed of a solid solution phase with fine crystal grains. Magnetization of Ni-9.5%Cr and Co-8.4%Cr alloy thin films with fine crystalline phase reached to saturation at ca. 2.5 kOe in perpendicular direction to the film plane while pure Ni and pure Co thin film with large crystal grains were hardly magnetized in the perpendicular direction. Soft magnetic properties were improved with increasing Cr content in the deposits.

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“…Cr-rich phase [31]. According to the phase diagram of Ni-Cr and Co-Cr binary alloy system [20], in Ni-Cr alloy with R Cr depo more than ca.…”

Section: Magnetic Properties Of Electrodeposited Ni-cr and Co-cr Alloysmentioning

confidence: 99%

Soft magnetic properties of Ni–Cr and Co–Cr alloy thin films electrodeposited from aqueous solutions containing trivalent chromium ions and glycine

2012

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“…The areal density beyond 200 Gb/in 2 of LMR media will be limited. By designing an innovative recording mode (named as perpendicular magnetic recording, PMR), magnetic recording media with areal density exceeding 1 Tb/in 2 could be developed [1][2][3][4][5][6][7]. In contrast to LMR, the magnetic interactions between two neighbouring "0"and "1" bit cells in PMR media are attractive.…”

mentioning

confidence: 99%

Magnetic properties of perpendicularly orientated L10 FePt nanoparticles

Xiang

et al. 2010

Chin. Sci. Bull.

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L1 0 FePt films were deposited on MgO (001) substrates heated to 700°C by magnetron sputtering. Assisted by the misfit of lattice between film and substrate, strong (001) texture was formed. The film at nominal thickness t N = 5 nm was composed of nanoparticles with a size of ~70 nm, and showed a high coercivity of ~105 kOe at 4.2 K. At t N =~50 nm, as the film changed from discontinuous to continuous, the coercivity dropped about one order of magnitude. Micromagnetic simulation implies that the magnetization reversal is a vortex-like nuclear type. The ideal coercivity of a separated single-domain L1 0 FePt nanoparticle with a size of 70 nm× 70 nm× 5 nm is ~121 kOe. This tells us that the experimental coercivity has nearly reached the limit of ideal single crystalline nanoparticles. L1 0 FePt nanoparticle, coercivity, magnetization reversal, magnetic domain Citation: Mo X J, Xiang H, Li G Q, et al. Magnetic properties of perpendicularly orientated L1 0 FePt nanoparticles.Magnetic recording media for data storage is one of the most important applications of magnetic materials due to its nonvolatility and low cost per megabyte. In longitude mode (LMR, longitude magnetic recording), data are recorded by magnetizing a cluster of grains, called as a bit cell. The magnetic interactions between two oppositely magnetized neighbouring bit cells (represent data of "0" and "1", respectively) are repulsive. The areal density beyond 200 Gb/in 2 of LMR media will be limited. By designing an innovative recording mode (named as perpendicular magnetic recording, PMR), magnetic recording media with areal density exceeding 1 Tb/in 2 could be developed [1-7]. In contrast to LMR, the magnetic interactions between two neighbouring "0"and "1" bit cells in PMR media are attractive. Even the magnetization of each discrete grain can represent a bit of data [8]. The magnetization fluctuates randomly because of thermal energy, k B T, where k B is the Boltzmann's constant and T is the temperature. To avoid unstable magnetization due to a phenomenon called as superparamagnetism [9], the materials used in PMR media need to exhibit high uniaxial magnetocrystalline anisotropy energy (K u ). The near-stoichiometric L1 0 phase FePt alloy with K u = 7×10 7 erg/cm 3 has prompted intense research activity and is considered to be one of the most promising candidates for high density PMR media [10][11][12][13], as the magnetization energy barrier in a grain as small as 3 nm is enough to overcome thermal instability [14]. L1 0 FePt has face centered tetragonal (FCT) structure with lattice constants a = b = 0.3905 nm, and c = 0.3735 nm. It can be kept in air without oxidation due to its chemical stability. Its Curie temperature is about 750 K. Bulk FePt alloy synthesized at room temperature nominally adopts its high temperature disordered A1 phase (a random solid solution face centered cubic (FCC) structure,

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ChemInform Abstract: Magnetic Structures in Co‐Cr Media for Perpendicular Magnetic Recording

Lodder

1997

ChemInform

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Magnetic structures in CoCr media for perpendicular magnetic recording

Cited by 13 publications

References 45 publications

Soft magnetic properties of Ni–Cr and Co–Cr alloy thin films electrodeposited from aqueous solutions containing trivalent chromium ions and glycine

Soft magnetic properties of Ni–Cr and Co–Cr alloy thin films electrodeposited from aqueous solutions containing trivalent chromium ions and glycine

Magnetic properties of perpendicularly orientated L10 FePt nanoparticles

ChemInform Abstract: Magnetic Structures in Co‐Cr Media for Perpendicular Magnetic Recording

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