Masaaki Matsumoto

Vibration of head suspensions for proximity recording

The effect of friction force between the head slider and disk on the vibration of the head suspension assembly was simulated using Finite Element Method (FEM) analysis. Vibration of the slider in the transverse direction was measured using a Laser Doppler Vibrometer (LDV) in both the flying and proximity conditions. The vibration in the vertical direction of the head suspension was measured using a scanning LDV simultaneously. The effect of friction force on the vibration with different skew angles was investigated.

Properties Of Diamond-like Carbon Films And Its Application For Protective Layers Of Thin Film Magnetic Recording Disks

Wear rate of diamond-like carbon (DLC) protective layer deposited by a radio frequency plasma enhanced chemical vapor deposition method has been evaluated by continuous sliding tests using spherical sapphire pins. The influence of each property such as microstructure and microhardness on wear durability of the film is discussed. It has been found that the wear durability of the DLC film is several times superior to that of conventional sputtered carbon film. >

Measurement of Slider/Disk Collision Forces Using Acoustic Emission Source Wave Analysis

A new measuring technique has been developed for the purpose of analyzing the slider/disk collision phenomena. Very small piezoelectric sensors are mounted on the slider. These sensors detect elastic waves (acoustic emission) in the slider which are induced by the collisions at the slider rail surface. In order to obtain input collision force quantitatively, the transfer function of the slider, sensor, and electric circuit is measured by the breaking pencil lead method. The inverse operation is also performed by using source wave analysis. Force amplitude of the order of 4˜20 mN and contact time of the order of 5˜22 μ are detected. Two types of collision force are observed. One has large amplitude and narrow time width and is conjectured to arise from collisions with hard projections. The other has small amplitude and wide time width and is conjectured to arise from collisions with soft projections. Presented as a Society of Tribologists and Lubrication Engineers paper at the ASME/STLE Tribology Conferenc...

Friction force of negative pressure sliders for proximity recording

We investigated the friction force between the trailing edge of the center pad or rail of negative pressure sliders and the textured disk surface as a function of flying height at reduced air pressure. In addition, we proposed the simple contact model and compared experimental friction force with calculated contact force to evaluate the influence of slider design parameters on the contact force. Results show that the contact force is significantly influenced by the pitch air-bearing stiffness, the distance between the pivot point and the contact point, and the interference pitch angle defined as the difference between the flying pitch angle on the smooth glass disk and the contact pitch angle on the textured disk.

Design and performance of novel air bearing slider

Lower flying height provides higher recording density in magnetic disk drives. Therefore well-designed sliders are essential for higher recording density. In order to break the limits of conventional machined straight rail sliders, and also to make effective use of MR heads and constant density recording, a novel Parasol shaped slider using positive and negative pressure has been developed. This Parasol slider provides a constant flying height profile, stable low flying height, and debris elimination. >

Flying characteristics of advanced step sliders-optimization of sub-ambient step slider for decreasing sensitivity to altitude and velocity

We developed an advanced sub-ambient pressure step slider which consists of a step bearing with sub-micron depth and a cavity for generating sub-ambient pressure force to reduce variations of flying height caused by changing altitudes and disk velocities. We found that sensitivities of flying heights to altitudes and disk velocities strongly depend on the cavity depth and the step depth, respectively. The flying height change caused by altitude and disk velocity can be reduced by designing the cavity depth at which generated sub-ambient pressure forces shows maximal value and by designing the step depth of 0.2 /spl mu/m or less when the disk velocity is less than 35 m/s, respectively.