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Scanning Hall probe microscopy (SHPM) was used to evaluate integrated magnetic microactuators designed for hard disk drives. The Hall probe measurements of the generated magnetic field strength as a function of the applied current or distance were compared to results of a finite element method simulation. The SHPM measurements and simulation results are in good agreement, confirming that simulations supported by SHPM measurements can be used successfully to predict the performance of microactuators. [ABSTRACT FROM AUTHOR]

To replace NiFe alloys used as flux guides in magnetic microelectromechanical systems, electroplated CoFe thin films were examined. The films were deposited using pulse plating. The results show a strong influence of the reverse current Ireverse on the deposition rate and the saturation flux density Bs. The relative permeability μr is influenced both by the forward current Iforward and by reverse current Ireverse. Based on the examinations an optimized deposition was performed. A film thickness of 15 μm was reached during a deposition time of 1 h. This film exhibited a saturation flux density Bs of 1.4 T, a coercivity Hc of 1130 kA/m, and a relative permeability μr of 290. At this thickness, no delamination occurred and the film showed only minor signs of corrosion, a phenomenon CoFe films are typically prone to. [ABSTRACT FROM AUTHOR]

Efficient magnetic microactuators require a deposition and patterning of a permanent magnetic material. A material that can be deposited in the range of up to a couple of 10 μm is sputtered SmCo. For the fabrication of magnetic microactuators, alternative substrate materials besides silicon are of great interest. Therefore, alumina-ceramic as well as B270-glass substrates were included in the investigation. A maximum energy product of 90 kJ/m3 was achieved for rather thick layers of 30 μm deposited on glass or ceramic substrates. The latter substrates were found to be suitable for the deposition of SmCo layers up to a thickness of 50 μm. Furthermore, the SmCo exhibits isotropic magnetic properties, thus a magnetization of the permanent magnetic layer can be performed in plane as well as perpendicular to the film plane. For the patterning of these thick SmCo layers ion beam etching and wet chemical etching were examined. For both methods, the suitability of patterning thick SmCo layers could be demonstrated. For the integration of a SmCo permanent magnet in a magnetic microactuator, the two technologies for deposition and patterning of the SmCo layer had to be combined. Two linear microactuators are presented utilizing different integration methods of the SmCo component as well as direction of magnetization. [ABSTRACT FROM AUTHOR]

To develop a system integration process for a slider with an integrated microactuator (SLIM), quite a few challenges had to be resolved. They include processes for double rowbar stacking and thinning, chiplet mounting, slider separation, and chiplet cross crown fabrication, to name just a few. The slider separation process is particularly challenging: during this process, the mounting bars suspended on thin Si leaf springs are released. This paper discusses the challenges encountered and the system integration solutions developed. [ABSTRACT FROM AUTHOR]

Taking advantage of microelectromechanical system technology, a slider with an integrated microactuator (SLIM) for use in hard disc drives was devised. It allows both a lowering to the operating static flying height and a second-stage actuation for ultraprecision track following. By placing the read/write element on a small chiplet rather than on the trailing edge of a slider, the design promises to be cost competitive. This paper provides an overview over the research results achieved so far. It discusses the fabrication technology applied for fabricating both the micromagnetics and micromechanics and presents experimental dynamic test results on SLIM devices which-although not yet flyable-do have fully functional microactuators. [ABSTRACT FROM AUTHOR]

Magnetic force-enhanced gene delivery provides a promising method for an efficient transfection even to single cells. Conjugating genes with magnetic nanoparticles allows for the magnetic manipulation of these complexes. This paper presents the concept, modeling, and fabrication technology for a magnetic microactuator designed as a pole row for magnetically actuating these complexes. For conducting preliminary tests, a scaled-up model of the micro pole row was created. [ABSTRACT FROM AUTHOR]

The paper describes the tests performed to determine the characteristics of four various leaf springs, as well as the evaluation of the mounting platform/chiplet motion as a function of the excitation current. For the leaf spring evaluation, a nanoindenter (Hysitron Tribo Indenter) was used. To determine the variation of the air gap as a function of the excitation current, optical microscopy as well as laser Doppler vibrometry (LDV) was applied. [ABSTRACT FROM AUTHOR]

A slider with an integrated microactuator (SLIM) was devised, which is capable of actuating a read-write element of a hard disc drive (HDD) in both vertical direction (adjusting the flying height) and in lateral direction (allowing second stage actuation). The read-write element is located on a chiplet attached to a mounting platform. A pair of integrated electromagnetic microactuators appropriately activates this mounting platform and thus the read-write element. This design promises a cost competitive solution for HDD recording head microactuation. While the SLIM design as well as the thin-film fabrication of the SLIM component parts were completed, a 40: 1 model allowed for initial system level experimental measurements which indicate a good agreement between the performance of the model and the actual SLIM device. [ABSTRACT FROM AUTHOR]

A slider with an integrated microactuator (SLIM) allows actuating a read-write element of a hard disk drive (HDD) in both the vertical direction allowing a flying height adjustment as well as in the lateral direction allowing a second stage actuation. The microactuator system consists of a pair of electromagnetic variable reluctance (VR) micro actuators. The microactuator system is fabricated using thin-film technology. Each actuator has a permalloy C-core carrying a two-layer spiral Cu coil with a total of 16 turns. The insulation materials are SU-8 (in the lateral direction) and Si3N4 (in the vertical direction). The total size of one magnetic VR microactuator is 460 µm x 300 µm x 61 µm. This paper discusses design considerations, presents the FEM simulation conducted, describes the fabrication technology, and provides experimental results. [ABSTRACT FROM AUTHOR]

In linear micro-actuators based on the electromagnetic driving principle, attractive vertical forces are generated between stator and traveler in addition to the drive forces. These vertical forces reduce the resulting driving force of the motor depending on the quality of the applied guide system. Thus, the development of an adequate guide system with a very small friction is required to guarantee an efficient operation mode. This paper describes the development of a guide system based on repulsive magnetic forces to partially compensate the vertical forces of a linear hybrid step micromotor. [ABSTRACT FROM AUTHOR]