Takayuki Ichihara

Soft magnetic and crystallographic properties of Ni/sub 81/Fe/sub 19//Co/sub 67/Cr/sub 33/ multilayers as backlayers in perpendicular recording media

Multilayers composed of Ni/sub 81/Fe/sub 19/ and paramagnetic Co/sub 67/Cr/sub 33/ interlayers were prepared by facing targets sputtering as backlayers for perpendicular magnetic recording media. This multilayered film must satisfy the requirements for both improvement of (111) plane orientation and for providing excellent soft magnetic properties. Co/sub 83/Cr/sub 17/ recording layers deposited onto [Ni/sub 81/Fe/sub 19//Co/sub 67/Cr/sub 33/(50 /spl Aring/)]/sub n/ multilayers exhibited good c-axis orientation as a consequence of lattice matching with the (111) oriented fcc Ni-Fe plane. This effect was further improved by depositing the multilayer on to paramagnetic Co/sub 67/Cr/sub 33/ layers. Soft magnetic properties of Ni-Fe layers were also improved by forming multilayered structure. Ferromagnetic resonance (FMR) studies indicated that there is no significant interdiffusion in the multilayered structure. FMR also suggest that one of the origins of soft magnetism in the multilayers was related to the reduction of inhomogeneity of localized anisotropy. Increased Knoop hardness of the multilayers was also observed using multilayers. >

Theory, fabrication and testing of dual track complimentary type of thin‐film recording heads for perpendicular magnetic recording system

A new type of recording head for a perpendicular magnetic recording system, a dual track complimentary (DTC) type of thin‐film head, was proposed in this study. The magnetic core of the head has a ‘‘U’’ character shape which is provided with ‘‘a pair of’’ recording tracks and the efficiency to detect flux reversal in the media will become high enough to achieve high linear density. The two‐dimensional analysis of DTC heads implied that the perpendicular component of the head field should become larger by using the double‐layered media under a narrower spacing condition. Recording characteristics using conventional ring head were evaluated in order to determine the principle of DTC configuration. Several DTC heads were prepared using photolithography technique and their performances were examined. A typical DTC head has inductance of about 500 nH, which is relatively low, and constant up to 10 MHz. DTC heads seems to be one of the most hopeful candidates as the heads useful for perpendicular magnetic recor...

Three-dimensional analysis of dual track complementary type of heads for perpendicular magnetic recording

The reproduction flux distributions of the dual track complementary (DTC) type of heads for perpendicular magnetic recording were calculated using a 3-D finite element method and compared with those of the single pole type (SPT) of heads. The calculated reproduction flux hardly changed along the head pole, which indicates that the flux sensitive detector can be placed far from the air bearing slider surface in the DTC head system. As a result, the DTC type of recording heads may be a candidate for heads for perpendicular magnetic recording systems.

Improvement of micromagnetism of Ni-Fe/Co/sub 67/Cr/sub 33/ multilayers for backlayers of perpendicular magnetic recording media

The multilayers composed of soft magnetic Ni/sub 79/Fe/sub 21/ layers and very thin paramagnetic Co/sub 67/Cr/sub 33/ layers were deposited using the facing targets sputtering (FTS) apparatus. When the external field H/sub ext/ of 100 Oe transverse to the direction of the plasma confining field H/sub p/ of about 20 Oe in the FTS apparatus was applied during layer deposition, the soft magnetic characteristics for the [Ni/sub 79/Fe/sub 21//Co/sub 67/Cr/sub 33/]/sub 2/ multilayers were improved. Furthermore, the relative permeability /spl mu//sub r/ of the multilayers was extremely and isotropically increased especially when the multilayers were deposited at extremely low Ar pressure P/sub Ar/ of 0.4 mTorr.

TWO STEP SPUTTERING METHOD AND ITS APPLICATION TO PREPARATION OF BILAYER MEDIA

The crystallinity of Co-Cr recording layer and Ni-Fe backlayer is important for perpendicular magnetic recording media with Co- Cr/ Ni-Fe double layer. Two step sputtering method was proposed to improve the crystallinity of not only Co-Cr layer but also Ni-Fe one. The Co-Cr underlayer as ultra-thin as lOOA is very helpful for enhancing the c-axis orientation of Co-Cr crystallites and orientation of Ni-Fe ones. The multilayers composed of Ni-Fe and ultra-thin Co-Cr layers revealed very soft magnetism and excellent orientation for the Ni-Fe layers. These multilayers were properly effective for the hetero-epitaxial growth of Co-Cr recording layer deposited on them.