Search

To take the interparticle magnetic interaction into account, the mean field theory was introduced into our magnetic recording simulator based on a finite element method and the curling magnetization switching model. Remanence curves and Henkel plots were well simulated by computer for Ba-ferrite media which exhibit the large positive interparticle interaction. The perpendicular magnetic recording performance is strongly influenced by the interparticle interaction. A larger reproduced voltage is obtained when the interaction is stronger.

Reciprocity as conventionally used for a theoretical calculation of reproduced voltage in magnetic recording has been examined by the newly developed magnetic recording simulator. The recording characteristics are influenced by the magnetic interaction between a head and a medium, especially in perpendicular magnetic recording combined with a single-pole head and a Co-Cr/Ni-Fe medium. To investigate the influence of the head-medium magnetic interaction on reciprocity, reproduced waveforms calculated by reciprocity have been compared with those obtained by the simulator. We have confirmed that reciprocity completely holds independently of the head-medium magnetic interaction when the head field distribution in the absence of a recording layer of a medium has been used for the head sensitivity function in reciprocity integral.

Fe-N-Al-O alloy films were fabricated by rf reactive sputtering in a mixed Ar+[N.sub.2] plasma. The Al and O contents in films were varied by the area ratio of [Al.sub.2][O.sub.3] chips placed on an Fe target. We examined the effects of additional elements, such as Al and O, on magnetic and electrical properties of the Fe-N-Al-O films, and we investigated the relationship between soft magnetic properties and microstructure. The permeability reaches a maximum of about 1800, when the Al+O content range is 10-16 at%. Fe-N-Al-O films in this range have 4[Pi]Ms = 19-20 kG and [Rho] = 60-100 [micro][Omega]cm. The real part of permeability ([Mu]') of the 0.7-[micro]m-thick [Fe.sub.79][N.sub.5][Al.sub.6][O.sub.10] film remains constant up to 300 MHz. The as-deposited Fe-N-Al-O film showing soft magnetic properties has homogeneous microstructure with a grain size of about 5 nm. It seems that the addition of Al and O to Fe-N films is effective in suppressing grain growth, and contributes to the formation of homogeneous film structure. Index Terms--Fe-N-Al-O film, resistivity, saturation magnetization, soft magnetic properties, sputtering.

Fundamental design considerations of the write head for a hard disk drive with a higher data transfer rate are described. With a shorter yoke, the eddy current dumping can be suppressed effectively. The head inductance is also reduced by yoke length reduction so that the rise time of write current can be reduced. To reduce yoke length, we adopted a double layer coil, which enabled us to increase coil winding turns. With half yoke length and the coil turns increase, we successfully reduced the NLTS by about half. The FIB pole trimming at wafer level can make an appropriate pole shape for generating a highly efficient writing field. Index Terms--Field rise times, high data rate, NLTS, write head, yoke length.