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To guarantee a successful fabrication of magnetic micro devices, attaining the desired properties of magnetic thin- films is a precondition. This is particularly true for anisotropic magnetic films. This paper presents the development and fabrication of a micro hysteresis sensor chip consisting of two independent sensors oriented perpendicular to each other. Such an approach allows measuring the properties of anisotropic magnetic thin-films along the two desired axes. The paper describes design, fabrication, and evaluation of the micro hysteresis sensor. Index Terms--BH-loop, magnetic MEMS, micro hysteresis sensor, thin-film technology.

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 [Si.sub.3][N.sub.4] (in the vertical direction). The total size of one magnetic VR microactuator is 460 [micro]m x 300 [micro]m x 61 [micro]m. This paper discusses design considerations, presents the FEM simulation conducted, describes the fabrication technology, and provides experimental results. Index Terms--Electromagnetic microactuator, flying height adjustment, second stage actuation.

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. Index Terms--Electromagnetic microactuator, flying height adjustment, second stage actuation.

In order to manufacture sliders for rigid disk drive recording heads, some of the most sophisticated precision machining technologies available today have been developed. These technologies include grinding operations for both slicing and profiling of sliders, as well as lapping or nanogrinding for the ultraprecision machining of the air bearing surfaces. Due to a continuous decrease in slider size as well as flying height, a further reduction of the defects is required. This paper provides an overview of slider machining requirements, discusses the cutting process parameters, and presents the nanogrinding process, which is especially well suited for air bearing surface (ABS) machining.

An active magnetic levitation system based on repulsive magnetic forces was developed as a guide for a linear hybrid microstep motor. With this levitation system, the vertical force, which is typically an order of magnitude greater than the driving force, can be compensated. A capacitive measurement system provides measurement data to maintaining a constant air gap. This paper presents the design, fabrication, and first measurement results of the magnetic guide and the air gap measurement sensor. Index Terms--Electromagnetic drive, linear micromotor, magnetic levitation, microassembly.

A highly sensitive micro strain gauge may be created by building up a thin-film micro transformer with one leg of its flux guide made out of magnetoelastic material. Locating the magnetoelastic leg at the bottom of the micro transformer structure directly on top of the wafer lends itself for integration in a cantilever beam subjected to bending. On the other hand, putting the magnetoelastic layer on top and placing it on an external tension bar instead of integrating it into the sensor allows for strain measurement without exposing the strain gauge itself to stain. By choosing a modular design, both types of micro transformers may be fabricated in the same wafer process. This paper describes design, fabrication, and performance of such a modular system. Index Terms--Magnetoelastic material, micro strain gauge, micro transformer, thin film technology.

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. Index Terms--Magnetic guide, magnetic levitation, micro-actuator, micro-coil, thin-film technology.

A magnetic field modulation (MFM) micro coil was developed and fabricated as part of a magnetooptical recording system. The center of the coil is transparent, allowing a beam of blue laser light to pass through and heat up locally the magnetooptical storage layer, which is then magnetized by the micro coil for data recording. The micro coil therefore not only needs to be located at a very small working distance ( 0.8) and the disc. As a result, the micro coil has to be fabricated on a glass wafer being only 100 [micro]m thick, which posed considerable technology challenges. To match these requirements, a microcoil was developed which fulfills the system integration and operating requirements of the magnetooptical system. Index Terms--Magnetooptical recording, micro coil, thin-film technology.

The development of an optical recording system which is based on the flying head technology requires to determine the head's dynamic flight behavior. To do so, a thermo-resistive test head was created. It uses thermo-resistors embedded in the air-bearing surface (ABS). Joule heating by the sensing current generates a heat flow across the head-disk spacing which highly depends on the distance between ABS and disk. Due to the thermal sensors located on each of the four corners of a slider, pitch, roll, and flying height variations may be measured. Index Terms--Flying heads, magnetooptical data storage, thin-film technology.

To increase storage capacity, an advanced magneto-optical recording technology using high numerical aperture (NA) optics (NA>0.8) in combination with a micro coil creating a local magnetizing field has been investigated. For data recording, a beam of blue laser light locally heats up the magneto-optical storage layer, which is then magnetized by the micro coil. The micro coil therefore needs to be located at a very small working distance (< 50 [micro]m) from the disks, which requires the magnetic coil to be mounted between the lens and the disk. Furthermore, the substrate has to be transparent to allow the laser beam to pass through the center of the magnetizing coil. The microcoil that has been developed has proven capable of creating the magnetic field required for magneto-optical recording, could operate at the required recording frequencies, and promises sufficient heat dissipation. Index Terms--Magneto-optical recording, micro coil, thin-film technology.

An eddy-current microsensor for proximity measurement was developed. To achieve an optimal design, the sensor was modeled using the finite-element method. By studying the sensor response, but staying within the technological boundaries, an optimal design was reached. The sensor had a soft-magnetic core and separate excitation and pickup coils. The fabrication technologies included electroplating for core and coil and sputter deposition for insulation and seed layers. Photoresists were used for creating micromolds for electroplating both core and coil, as well as for sensor embedding. Completed sensor samples had a frequency range of 100 kHz to 2 MHz and proved their capability of performing proximity measurement. Index Terms--Eddy-current sensor, microsensor, proximity measurement.

The influence of breaking the vacuum while depositing an exchange coupled multilayer system for a GMR spin valve sensor was investigated, focusing particularly on the relationship between etching time and exchange coupling properties of the antiferromagnet to the ferromagnet. A [Cr.sub.46][Mn.sub.46][Pt.sub.8] antiferromagnet was used to induce a unidirectional anisotropy in a [Ni.sub.81][Fe.sub.19] ferromagnetic layer. Typically, the exchange coupled 30 um CrMnPt/12 um NiFe films exhibited an exchange field of approximately 80 Oe by depositing the layers without breaking the vacuum and no consecutive annealing process. Unloading the NiFe layer and exposing it to the air required a sputter etching process before depositing the antiferromagnet to accomplish exchange coupling. For achieving optimal results, the etching time has to match the time required for removing the oxide film but not for etching the NiFe layer any further. However, layer systems deposited by breaking the vacuum displayed a reduction of the exchange field of roughly 50%. Index Terms--Exchange biasing, exchange coupling, GMR spin valve sensor, sputter deposition with breaking the vacuum.

The use of anisotropic magnetoresistive (MR) heads at low flying height has led to the phenomenon of thermal asperities, read signal spikes caused by thermal effects when a slider impacts disk asperities. This paper presents a proposal for a wide trackwidth thermal asperity test head with a dual stripe sensor on a picoslider. While it turns out that a single stripe is sufficient to detect thermal asperities, a dual stripe sensor has the added advantage of being capable of reading magnetic index marks on the disk. This allows one to trace an asperity location after the disk has left the test stand. A thermal asperity signal waveform typically starts out with an undershoot. This effect is caused by greatly enhanced sensor cooling due to a reduction of the head to disk clearance when approaching the thermal asperity. Index Terms - Thermal asperity test head, picoslider, dual stripe sensor, thermal asperity signal waveform.

Several experimental studies are conducted to explain new strategies that can be adopted for the optimization of the electroplating process of the various CoFe microelectromechanical systems. The plating process is shown to be highly improved by the different efficiencies of the applied additives.

Scanning Hall probe microscopy (SHPM) is used for evaluating the integrated magnetic microactuators designed for hard disk drives. The SHPM measurements and simulations results have confirmed that simulations supported by SHPM measurements have successfully predicted the performance of microactuators.

The effect of film stress caused by different coefficients of thermal expansion of substrate and magnetic film is examined. The studies have shown that the stress can be minimized when using a soft magnetic material with a coefficient of thermal expansion close to the one of the substrate.

Electroplated CoFe thin films were examined to replace NiFe alloys used as flux guides in magnetic microelectromechanical systems. The results show that the CoFe thin films might serve as a replacement for the currently used electroplated JiFe thin films, but not as an improvement on them.

Sputtered SmCo, alumina-ceramic and B270 glass substrates are investigated for use in electromagnetic microactuators. Two linear micractuators utilizing different integration methods of the SmCo component as well as direction of magnetization, are presented.