L10-CoPt Bit Patterned Media with Tilted Easy Axis for Ultrahigh Areal Density over 2.5 Tb/in2

2014 ◽  
Vol 931-932 ◽  
pp. 1255-1259
Author(s):  
Arkom Kaewrawang
Keyword(s):  
Easy Axis ◽  
Areal Density ◽  
Disk Drive ◽  
Simulation Software ◽  
Bit Patterned Media ◽  
Patterned Media ◽  
Perpendicular Media ◽  
Data Density ◽  
Superparamagnetic Limit ◽  
The One

Ultrahigh areal density is the key target of hard disk drive technology. Hence, writing field strength from head and switching field, Hsw, of media should be improved. In this work, we propose the one of alternative method to increase data density and reduce Hsw of the media by using tilted easy axis technology for bit patterned media (BPM) at areal density beyond 2.5 Tb/in2. Moreover, transition noise and superparamagnetic limit have been eliminated owing to characteristics of BPM. The effect of exchange coupled between adjacent bits, Adot, of tilted easy axis of BPM is analyzed by micromagnetic simulation software - the object oriented micromagnetic framework based on Landau-Lifshitz-Gilbert equation. The BPM with tilted easy axis perform clearly the reduction of Hsw below perpendicular media and available writing head field. The Adot of BPM has no effect on decreasing Hsw. Anisotropy and Zeeman energy density of BPM with tilted easy axis are higher and lower than perpendicular BPM, respectively. Thereby, BPM with tilted easy axis have high potentiality to improve Hsw of media at ultrahigh data density.

Effects of Magnetic Properties of L10-CoPt based Bit Patterned Media with Tilted-Easy Axis on Switching Field at Areal Density over 2 Tb/in2

2015 ◽  
Vol 781 ◽  
pp. 207-210
Author(s):  
Arkom Kaewrawang
Keyword(s):  
Magnetic Properties ◽  
Easy Axis ◽  
Magnetocrystalline Anisotropy ◽  
Areal Density ◽  
Anisotropy Constant ◽  
Magnetic Media ◽  
Switching Field ◽  
Bit Patterned Media ◽  
Patterned Media ◽  
Easy Direction

Decrease of a switching field, Hsw, of the magnetic media with high magnetocrystalline anisotropy constant, Ku, can be handled by tilted-easy axis. Not only tilting easy direction of crystal but also optimum magnetic properties can improve writability. The effects of Ku and saturation magnetization, Ms, of L10-CoPt material of BPM with 45° tilted-easy axis are investigated in this article. The object oriented micromagnetic framework package based on Landau - Lifshitz - Gilbert equation has been used to analyze the magnetic properties of media in this paper. The results indicate that the Hsw decreases with decreasing Ku and increasing Ms. To achieve the Hsw lower than the maximum write head field, the Ku and Ms values should not be over 1.30 MJ/m3 and should exceed 0.30 MA/m, respectively.

scholarly journals Micromagnetic Simulation of L10-FePt-Based Exchange-Coupled-Composite-Bit-Patterned Media with Microwave-Assisted Magnetic Recording at Ultrahigh Areal Density

Micromachines ◽  
2021 ◽  
Vol 12 (10) ◽  
pp. 1264
Author(s):  
Pirat Khunkitti ◽  
Naruemon Wannawong ◽  
Chavakon Jongjaihan ◽  
Apirat Siritaratiwat ◽  
Anan Kruesubthaworn ◽  
...  
Keyword(s):  
Magnetic Recording ◽  
Magnetic Domain ◽  
Hysteresis Loops ◽  
Areal Density ◽  
Bit Patterned Media ◽  
Patterned Media ◽  
Microwave Assisted ◽  
The Media ◽  
5 Ghz ◽  
Exchange Coupled Composite

In this work, we propose exchange-coupled-composite-bit-patterned media (ECC-BPM) with microwave-assisted magnetic recording (MAMR) to improve the writability of the magnetic media at a 4 Tb/in2 recording density. The suitable values of the applied microwave field’s frequency and the exchange coupling between magnetic dots, Adot, of the proposed media were evaluated. It was found that the magnitude of the switching field, Hsw, of the bilayer ECC-BPM is significantly lower than that of a conventional BPM. Additionally, using the MAMR enables further reduction of Hsw of the ECC-BPM. The suitable frequency of the applied microwave field for the proposed media is 5 GHz. The dependence of Adot on the Hsw was additionally examined, showing that the Adot of 0.14 pJ/m is the most suitable value for the proposed bilayer ECC-BPM. The physical explanation of the Hsw of the media under a variation of MAMR and Adot was given. Hysteresis loops and the magnetic domain of the media were characterized to provide further details on the results. The lowest Hsw found in our proposed media is 12.2 kOe, achieved by the bilayer ECC-BPM with an Adot of 0.14 pJ/m using a 5 GHz MAMR.

Impact of Touchdown Detection on Bit Patterned Media Robustness

2013 ◽  
Author(s):  
Jia-Yang Juang ◽  
Kuan-Te Lin
Keyword(s):  
Areal Density ◽  
Flying Height ◽  
Head Disk Interface ◽  
Bit Patterned Media ◽  
Patterned Media ◽  
Disk Interface ◽  
Recording Process ◽  
Friction Temperature ◽  
The Media ◽  
The Impact

Bit patterned media (BPM) is considered as a revolutionary technology to enable further increase of areal density of magnetic recording beyond 1 Tbits/in2 [1]. Implementing BPM technology, however, significantly increases the complexity of the recording process, but also poses tremendous tribological challenges on the head-disk interface (HDI) [2]. One of the major challenges facing BPM is touchdown detection by thermal flying-height control (TFC), in which a minute heater located near the read/write transducers is used to thermally protrude a small portion of the slider into contact with the disk, and the contact is then detected by directly or indirectly measuring the friction, temperature rise or vibration caused by the contact [3]–[7]. Most recording heads rely on touchdown detection to achieve a desired flying height (FH), which approaches sub-1-nm regime for many of today’s commercial drives. As a result sensitive and accurate touchdown detection is of critical importance for a reliable head-disk interface by reducing contact duration and unnecessary interaction between the slider and the disk. However, the impact of touchdown on the mechanical robustness of the media has not been properly studied.

Trellis-Based Detecting the Insertion and Deletion Bits for Bit-Patterned Media Recording

2014 ◽  
Vol 979 ◽  
pp. 54-57 ◽  
Author(s):  
Santi Koonkarnkhai ◽  
Piya Kovintavewat ◽  
Phongsak Keeratiwintakorn
Keyword(s):  
Detection Method ◽  
Signal To Noise Ratio ◽  
Areal Density ◽  
Specific Marker ◽  
Magnetic Medium ◽  
Bit Patterned Media ◽  
Patterned Media ◽  
Media Noise ◽  
Insertion And Deletion ◽  
Better Than

Bit-patterned media recording (BPMR) is one of the promising technologies for realizing an areal density up to 4 Tb/in2; however, it poses new challenges to read channel design, including the two-dimensional (2D) interference, media noise, and track mis-registration. Furthermore, the BPMR system encounters the insertion, deletion and substitution errors, which are primarily caused by mis-synchronization between the write clock and the island positions. In this paper, we propose a novel detection method that exploits the trellis structure to detect the occurrence of insertion/deletion bits. Specifically, the specific marker bits are inserted periodically inside an input data sequence before recording onto a magnetic medium. Hence, the branch metric calculation is monitored during the marker bits to determine if there is any insertion/deletion error in the system. Numerical results indicate that the proposed method can performs better than the conventional one in terms of the percentage of detection and the percentage of missed detection and false-alarm, especially at low signal-to-noise ratio scenario.

Contribution of the easy axis orientation, anisotropy distribution and dot size on the switching field distribution of bit patterned media

2011 ◽  
Vol 99 (6) ◽  
pp. 062505 ◽  
Author(s):  
Jehyun Lee ◽  
Christoph Brombacher ◽  
Josef Fidler ◽  
Barbara Dymerska ◽  
Dieter Suess ◽  
...  
Keyword(s):  
Field Distribution ◽  
Easy Axis ◽  
Switching Field ◽  
Bit Patterned Media ◽  
Axis Orientation ◽  
Patterned Media ◽  
Orientation Anisotropy ◽  
Switching Field Distribution

Microwave Assisted Magnetization Reversal on Exchange Coupled Composite Media

2014 ◽  
Vol 931-932 ◽  
pp. 1265-1269 ◽  
Author(s):  
Naruemon Wannawong ◽  
Warunee Tipcharoen ◽  
Arkom Kaewrawang
Keyword(s):  
Magnetic Recording ◽  
Magnetization Reversal ◽  
Microwave Field ◽  
Single Layer ◽  
Microwave Frequency ◽  
Areal Density ◽  
Disk Drive ◽  
Microwave Assisted ◽  
Superparamagnetic Limit ◽  
Exchange Coupled Composite

To overcome superparamagnetic limit, microwave assisted magnetic recording (MAMR) is one interesting magnetic recording technology. Therefore, the effect of microwave on magnetization reversal in media should be analyzed. In this work, we propose the MAMR to decrease switching field (coercivity, Hsw) in exchange coupled composite (ECC) media by using the micromagnetic simulation based on the Landau - Lifshitz - Gilbert equation. The Hsw of single layer and ECC media without microwave field is 110.90 and 7.7 kOe, respectively. When the oscillating microwave field is added, Hsw of single layer media with microwave frequency of 2.5 - 40 GHz is lower than 110.90 kOe. Likewise, Hsw of ECC media with microwave frequency of 5 - 16 GHz is lower than 7.7 kOe and has the lowest value of 4.9 kOe at frequency of 10 GHz. The results from this work lead to solve superparamagnetic limit and increase areal density in hard disk drive.

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