Edge Printing Research Articles

蒸着テープを用いた垂直磁気転写解析

The duplication characteristics of perpendicular magnetic media were analyzed by using metal evaporated (ME) tape as a slave medium. In the case of bit printing (BP), the best duplication characteristic was obtained at a duplication field of 4 kOe, about 2 times higher than the coercivity of the ME tape. On the other hand, in the case of edge printing (EP), duplication characteristics were saturated when the duplication field was more than 3kOe. When the duplication field was strengthened, in the case of BP, the peak position shifted towards the outside of the magnetic layer of the master, whereas, in EP, the peak position shifted towards the center of the magnetic layer. The calculated MFM output waveform obtained by using computer simulation almost coincided with the experimental result, and the cause of the sub-peak could thus be explained. It was concluded that EP has better duplication characteristics than BP.

Influence of Soft-under-layer in Perpendicular Recording Media on Recording field of Magnetic Duplication

The magnetic field distributions around slave media with and without SUL were calculated by using the finite element method to estimate what influence a soft-under-layer (SUL) in a double-layered perpendicular medium had on magnetic duplication characteristics. As a result, we found the SUL enhanced duplication characteristics for any bit length and track width. The SUL in bit printing influences the duplication characteristics more than that in edge printing. The influence of SUL on duplication characteristics in bit printing increases as the strength of the duplication field increases. However, in edge printing, there is a duplication field that maximizes the influence of SUL on duplication characteristics. Moreover, the influence of SUL on duplication characteristics decreases with both bit and edge printing as bit the length of the magnetic pattern decreases, and also decreases as the track width decreases. These dependencies can be explained by taking the demagnetization coefficient of SUL and the total amount of magnetic charge appearing in SUL and magnetic patterns into account.

マスターディスクの飽和磁化が垂直磁気転写特性に及ぼす影響

The influence of saturation magnetization of a master disk on its perpendicular magnetic contact duplication characteristics was investigated by using the two-dimensional finite element method. An investigation of bit printing (where the duplication field is applied in a direction perpendicular to the disk plane) and edge printing (where the duplication field is applied in an in-plane direction), revealed the following points. In bit printing, the influence of saturation magnetization of a master disk on perpendicular duplication characteristics is very small when the duplication field is nearly equal to the coercivity of the slave (4 kOe), which is the optimum field. On the other hand, in edge printing, the duplication characteristics are better for high saturation magnetization of a master disk than for low saturation magnetization. The cause of this difference in the influence of saturation magnetization of a master disk is the demagnetizing field of the master. In bit printing, the influence of saturation magnetization of a master disk is small because of the high demagnetizing field coefficient, while in edge printing, the influence of saturation magnetization of a master disk is large because of the low demagnetizing field coefficient.

Analysis of Perpendicular Magnetic Contact Duplication by Using Enlarged Model

Experiments on perpendicular magnetic contact duplication by using enlarged models were conducted, where we investigated what influence the strength of the duplication field and the magnetic layer thickness of the master had on duplication characteristics. Excellent duplication characteristics were obtained with bit printing when the duplication field was around the value of the coercivity of the slave, and the duplication characteristics improved as the magnetic layer of the master became thicker. In edge printing, the duplication characteristics improved as the duplication field was increased up to a certain field strength, above which the characteristics saturated, and barely depended on the thickness of the magnetic layer in the master. When their duplication magnetizations were compared, edge printing was more advantageous than bit printing.

Potential of Servo Pattern Printing on PMR Media With High-Density Servo Signal Pattern

Servo pattern printing (SPP) is recognized as a candidate for the future high resolution and high throughput servo track writing method. In terms of the application to perpendicular magnetic recording (PMR) media, there are two methods of SPP, "edge printing (EP)" and "bit printing (BP)," which use horizontal and vertical external field during printing process, respectively. Comparing between EP and BP, EP has higher potential for the PMR application, because of the properties of a dc-free signal, a higher signal-to-noise ratio (SNR) and smaller repeatable run out (RRO) from 8th to 19th order than a conventional head writing method. In the simulation, the less write-fringe of the recorded bits was confirmed as the benefits of EP. The most recent experiment demonstrated 55-nm bit length (BL) with adequate read back signal and EP is considered to have adaptability to the areal density beyond 48 Gbits/cm <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sup> (300 Gbpsi)

Interface Interaction Controlled Transport of CdTe Nanoparticles in the Microcontact Printing Process

High-quality CdTe nanoparticles stabilized with thioglycolic acid (TGA) are patterned on SiO2/Si surfaces using microcontact printing (microCP). Due to the weak interaction of the nanoparticles with the stamp surface, tailoring of gas flow rate during the inking process as well as the type and scale of the patterns on the stamp are used to control the distribution of the nanoparticles on the structured stamp surface. This distribution is then transferred the printed regions. Either edge printing or homogeneous printing can be achieved under optimized conditions. In addition, new structures such as nanowires form under certain conditions.