Effect of microstructure on media noise of CoCrTa thin film media fabricated under ultra clean sputtering process

Nakai, Junichi; Kikuchi, Akira; Kuwabara, M.; Sakurai, Takeshi; Shimatsu, T.; Takahashi, Minoru

doi:10.1109/20.490167

Cited by 19 publications

(4 citation statements)

References 4 publications

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“…In particular, a number of papers have reported a significant improvement in recording performance in Co-alloy media produced by ultraclean sputtering [7,10]. In recent work, we have shown that this improvement in recording performance lies in the reduction of crystallographic defects or stacking faults caused by residual nitrogen gas in the sputtering chamber [11].…”

Section: Introductionmentioning

confidence: 89%

Crystallographic defects in CoCrPt thin film media: effect on interactions and magnetic viscosity

Laidler¹,

Holloway²,

O'Grady³

2002

J. Phys. D: Appl. Phys.

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We report synchrotron x-ray and magnetic measurements on a set of five CoCrPt thin films, each sputter-deposited onto CrV underlayers after successively increasing the base pressure to which the system was pumped prior to charging with argon. We find that the increase of residual nitrogen gas in the chamber promotes the formation of fcc-like regions in the mainly hcp Co-alloy grains by increasing the stacking fault density. The type and probability of stacking faults were determined from the x-ray data and were found to increase with increasing base pressure, varying from 9% to 30% for samples grown at 10-8 and 10-4 Torr, respectively. These stacking faults cause an increase in regions of low coercivity thus promoting thermally activated magnetization reversal. We have examined the irreversible magnetization reversal processes and interactions in detail using remanence, ΔM and magnetic viscosity measurements. ΔM measurements provide a measure of the intergranular interactions. Significant differences were observed in the switching field distributions and ΔM curves. A large increase in activation volume was also observed for films with over 20% stacking faults. We propose that this is due to the reduction in the anisotropy fields caused by the crystallographic defects which then allows exchange coupling to dominate the reversal, causing cooperative reversal. We have also investigated the degree of in- and out-of-plane c-axis texture in the films and find that this is also dependent on the level of nitrogen contamination, as the c-axis texture is very poor in the film grown in the worst vacuum conditions. In the other films we see evidence of some degree of circumferential c-axis texture in the plane of the sample.

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Section: Introductionmentioning

confidence: 89%

Crystallographic defects in CoCrPt thin film media: effect on interactions and magnetic viscosity

Laidler¹,

Holloway²,

O'Grady³

2002

J. Phys. D: Appl. Phys.

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“…Although the fabrication of single-domain nanocrystal particles might be achieved by various methods, [6][7][8][9] a Gaussian distribution of particle size may occur during the fabrication of thin films. It is difficult to obtain uniform singledomain particles.…”

Section: Introductionmentioning

confidence: 99%

Magnetic properties and microstructure of amorphous Co100−xTbx thin films

Kuo

1998

Journal of Applied Physics

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Amorphous Co 100Ϫx Tb x alloy thin films with the composition of xϭ7 -60 at. % were prepared by dc magnetron sputtering at various powers and argon pressures then annealing in vacuum. Effects of the composition, sputtering power, argon pressure, and annealing temperature on the parallel and normal to the film plane magnetic properties have been investigated. The analysis of transmission electron microscopy diffraction patterns and magnetic measurement data indicate that an amorphous film with isotropic magnetic properties can be produced after low temperature annealing. The maximum observed perpendicular coercivity was as high as 6000 Oe for the as-deposited Co-Tb amorphous films. A nearly magnetically isotropic amorphous Co-Tb film with in-plane coercivity of about 2080 Oe was obtained after annealing.

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“…These interfacial and microstructural conditions, which affects strongly these physical properties through intergranular magnetic coupling, should be exactly controlled in fabrication process. We have been proposing the new concept in controlling the microstructure, defined as ultra clean sputtering process (UC-process) and showing the remarkable magnetic properties induced [1][2][3][4][5][6][7][8][9]. In this paper, the relation between the cleanness during film deposition process and magnetic properties is widely reviewed in connection with their microstructures.…”

Section: Introducfionmentioning

confidence: 99%

Novel Magnetic Properties Introduced by Ultra Clean Sputtering Process

Takahashi

1998

J. Magn. Soc. Jpn.

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The ultra clean sputtering process (UC-process) was introduced in the fabrication of thin film media and spin valve type Ni-Fe/25at%Ni-MnlNi-Fe films to establish the new concept of controlling the microstructure and magnetic properties. The relation between cleanness during film deposition process and magnetic properties has been discussed in connection with their microstructure. The UC-process here presented enables the control of the fine structure of the thin films and resulted in excellent magnetic properties. This study demonstrates that the UC-procss is very superior to the normal process presently used and plays a dominant role for the thin film media and spin valve head fabrication.

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Effect of microstructure on media noise of CoCrTa thin film media fabricated under ultra clean sputtering process

Cited by 19 publications

References 4 publications

Crystallographic defects in CoCrPt thin film media: effect on interactions and magnetic viscosity

Crystallographic defects in CoCrPt thin film media: effect on interactions and magnetic viscosity

Magnetic properties and microstructure of amorphous Co100−xTbx thin films

Novel Magnetic Properties Introduced by Ultra Clean Sputtering Process

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