First-Order Reversal Curve Investigations on the Effects of Ion Implantation in Magnetic Media

Gaur, Nikita; Piramanayagam, S. N.; Maurer, Siegfried L.; Steen, S.E.; Yang, Hyunsoo; Bhatia, Charanjit S.

doi:10.1109/tmag.2012.2201457

Cited by 12 publications

(5 citation statements)

References 20 publications

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“…Hence, the highest fluence of 5 × 10 16 ion/cm 2 was further used for subsequent patterned media fabrication. Our previous studies on Sb + implantation have indicated that a fluence of 2 × 10 16 ions/cm 2 is sufficient to reduce magnetization to zero in Co-based alloys27. Because the saturation magnetization in FePt is larger than that of Co-based alloy, a slightly higher implantation fluence was necessary in this study to ensure that the magnetization could be reduced to zero.…”

Section: Resultsmentioning

confidence: 93%

“…In our recent study, we have reported through first-order reversal curves of magnetization that a heavy ion such as Sb + can dislodge the atoms from the host lattice, resulting in a lateral diffusion of host atoms27. This effect is not very severe in alloyed films such as hcp-CoPt, where the lateral diffusion of Co and Pt is only changing the composition.…”

Section: Discussionmentioning

confidence: 99%

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Lateral displacement induced disorder in L10-FePt nanostructures by ion-implantation

Gaur

Kundu

Piramanayagam

et al. 2013

Sci Rep

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Ion implantation is a promising technique for fabricating high density bit patterned media (BPM) as it may eliminate the requirement of disk planarization. However, there has not been any notable study on the impact of implantation on BPM fabrication of FePt, particularly at nano-scale, where the lateral straggle of implanted ions may become comparable to the feature size. In this work, implantation of antimony ions in patterned and unpatterned L10-FePt thin films has been investigated. Unpatterned films implanted with high fluence of antimony exhibited reduced out-of-plane coercivity and change of magnetic anisotropy from perpendicular direction to film-plane. Interestingly, for samples implanted through patterned masks, the perpendicular anisotropy in the unimplanted region was also lost. This noteworthy observation can be attributed to the displacement of Fe and Pt atoms from the implantation sites to the unimplanted areas, thereby causing a phase disorder transformation from L10 to A1 FePt.

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Section: Resultsmentioning

confidence: 93%

Section: Discussionmentioning

confidence: 99%

Lateral displacement induced disorder in L10-FePt nanostructures by ion-implantation

Gaur

Kundu

Piramanayagam

et al. 2013

Sci Rep

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“…The Ion fluences such as 1×10 15 , 5×10 15 , 1×10 16 , 2×10 16 ions/cm 2 for high energy and 1×10 15 , 5×10 15 , 1×10 16 , 5×10 16 ions/cm 2 for low energy implantations were chosen to modify the structural and magnetic properties of the magnetic films. [15][16][17][18] For a theoretical understanding of the effect of implantations, Transport of Ions in Matter (TRIM) program from Stopping and Range of Ions in Matter (SRIM)-2008.04 simulations 19 were employed. All experimental characterizations were performed using X-Ray Diffraction (XRD), Atomic/Magnetic Force Microscopy (AFM/MFM) and Alternating Gradient Magnetometer (AGFM).…”

Section: Methodsmentioning

confidence: 99%

Tailoring the structural and magnetic properties of masked CoPt thin films using ion implantation

et al. 2017

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The effects of ion implantations through a mask on the structural and magnetic properties of Co80Pt20 films were investigated. The mask was patterned using the self-assembly of diblock copolymers. For implantation, high (40 keV for 14N+ and 100 keV for 40Ar+) and low (7.5 keV for 14N+ and 4.5 keV for 40Ar+) energy 14N+ and 40Ar+ ions were used to modify the structural and magnetic properties of these films. X-ray diffraction and TRIM simulations were performed for understanding the structural changes due to ion implantations. These results revealed the intermixing of Co atoms in lower layers and lattice expansion in Co80Pt20 magnetic and Ru layers. A lateral straggling of Co caused an increase in the exchange coupling in the masked region. Depletion of Co atoms in Co80Pt20 layer caused a decrease in the anisotropy constant, which were further confirmed by the alternating gradient force magnetometer and magnetic force microscopy results. The magnetic force microscopy images showed an increase in domain width and domain wall width confirming the above-mentioned effects.

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“…Such a reduction in the H u is an indication of an increase in exchange coupling, as reported in previous works. 32 Figure 5 shows the FORC contours of set B samples. In a similar fashion to set A samples, the FORC contours of set B samples are also found elongated along the H u axis but the extent of elongation is not as significant as in set A samples.…”

Section: Methodsmentioning

confidence: 99%

Magnetic interactions in CoCrPt-oxide based perpendicular magnetic recording media

Tan

Varghese

Piramanayagam

2014

Journal of Applied Physics

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First order reversal curves (FORC) method has been reported to be an efficient tool to study interaction between grains and layers of magnetic materials. Although a few studies have been carried out on perpendicular recording media in the past, a study on the effect of systematic variation of exchange interaction in granular perpendicular magnetic recording media on FORC contours has not been carried out in detail. Such a study will help to understand the use of FORC better. In this paper, we have made a systematic set of samples in order to study the variation in exchange coupling and its effect on FORC contours. The pressure during the deposition of the second ruthenium layer and the magnetic layer was varied to alter the separation between the grains and hence the exchange interaction between the grains in the CoCrPt-oxide recording layer. In addition, the thickness of Co-alloy cap layer was used as an additional tool to control the exchange interaction between the magnetic grains. The results indicated that the interaction field obtained from the FORC does not vary in a significant manner when the changes in exchange interaction are small. In comparison, the peak intensity of the FORC shows a clear trend as the exchange coupling is varied, making it a more suitable parameter to study the exchange and magnetostatic interactions in systems such as magnetic recording media.

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First-Order Reversal Curve Investigations on the Effects of Ion Implantation in Magnetic Media

Cited by 12 publications

References 20 publications

Lateral displacement induced disorder in L10-FePt nanostructures by ion-implantation

Lateral displacement induced disorder in L10-FePt nanostructures by ion-implantation

Tailoring the structural and magnetic properties of masked CoPt thin films using ion implantation

Magnetic interactions in CoCrPt-oxide based perpendicular magnetic recording media

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