High-field gradient Cusp field single-pole writing head with front return yoke

Abstract

The relationship between single-pole head design and recording resolution was investigated in perpendicular recording. It has been found from the computer simulation that it is useful to make a narrow separation between the main pole and the return yoke at the trailing side of the cusp-field single-pole-type (CF-SPT) head. A new head structure with an additive return yoke on the head surface was proposed to realize the aforementioned structure. The new head was fabricated by depositing the soft magnetic thin film onto the air-bearing surface of the CF-SPT head, followed by slitting the film along the main-pole edges by a focused-ion-beam system. As a result, the new head that modified a pole configuration improved 50 value about 25 kFCI compared with the original CF-SPT head.

Shielded planar write head

“…Improvement of the field gradient was obtained for the gap length between the value corresponding to the head to SUL spacing and twice of that. This is similar tendency to the cusp-coil head with a conventional shielded pole structure [8].…”

Magnetic shield design of perpendicular magnetic recording head by using topology optimization technique

“…The equation for FEM is given as (1) where is the coefficient matrix, is the column vector of magnetic vector potential, and is the right-hand side vector. Taking the derivative of (1) with design variable in an element (2) (2) can be rewritten as follows: (3) where is the value obtained by solving (1). If the objective function is expressed as the function of the permeability in design domain and the magnetic vector potential, the sensitivity is given by (4) Substituting (3) into (4), (5) can be obtained:…”

“…T HE perpendicular magnetic recording system is considered as an important technique for the high density magnetic recording exceeding 100 Gb/in [1]. On the other hand, when the linear recording density (BPI) is increased, the erase of bits due to the stray field becomes remarkable.…”

Grooved soft-underlayer for double-layered medium

“…Side-shields of the write head for the ATI [1,2] and a discrete track medium for the TMR and the large MWW [3] have been reported to be crucial in a perpendicular magnetic recording system composed of a single-pole head and a double-layered medium with a soft-underlayer (SUL) [4]. It has been considered that circumferential grooves formed on the SUL also improve the TMR and the MWW.…”