Yoshio Fujii

Initializing process on direct overwrite method using exchange-coupled quadri-layered magneto-optical film

A direct overwrite mechanism of the exchange-coupled quadri-layered film using light intensity modulation has been investigation. The initializing process in the overwrite mechanism was studied. It was found that the writing layer had two different coercivities depending on the magnetization state of its adjacent layers. The coercivity of the writing layer in the initializing process was lower than that of the single layer. Thus, the overwrite recording was achieved with good recording characteristics. How this phenomenon plays a critical role in the initializing process was clarified. It was also found that this process occurred well above room temperature. >

High performance magneto-optical disks using double layered Tb-Fe-Co films

Magnetooptical disks using double-layered Tb-Fe-Co films have been developed to obtain a high carrier-to-noise ratio (CNR). The two layers, which have different compositions, are coupled by a magnetic exchange interaction. The recording characteristics and reliability of the double layer have been studied. Optimized double-layered Tb-Fe-Co films and SiN/sub x/ protective layers were fabricated on polycarbonate pregrooved substrates. Better than 50-dB CNR, wide power margin, and high recording sensitivity were obtained at 3.7 MHz for 30-mm disk radius and 1800-r.p.m. disk rotation speed. The result of acceleration testing showed that the disks exhibit high reliability. >

One picoliter ejection of solder droplets by an advanced molten solder ejection method

We have developed an advanced molten solder ejection method which realizes to eject 1 picoliter molten solder droplets. The molten solder ejection method has been developed as a technique to supply small solder balls. The authors have developed a newly designed solder ejection head and have confirmed that solder balls with almost no surface oxidation can be formed by using this head. The size of the molten solder droplets using this newly developed method is 1 picoliter, which is much smaller than the previous minimum droplet size of 22 picoliters. A standard deviation in position accuracy of 0.81 mum was achieved.