G.H.J. Somers's research while affiliated with Philips and other places

Publications (7)

Article
Pickup elements for string instruments, in particular for electric guitars, represent a new application area for magnetoresistive sensors. Recently we developed a sensor configuration with permanent magnets for this purpose. For the first experiments we used commercial anisotropic magnetoresistance sensors (Philips KMZ10) mounted on small ferrite b...
Article
The giant magnetoresistance (GMR) effect offers interesting new possibilities for sensor applications. A short overview is given of the GMR effect in relation to its application in (automotive and industrial) field sensors. In the past the thermal and magnetic stability could not fulfil the requirements for use in automotive and industrial environm...
Article
The technology of magnetoresistive element (MRE) fabrication and integration as well as some experimental results on the performance of anisotropic and giant magnetoresistive elements are discussed. Most emphasis is put on isolated MREs in specially designed test structures, although results on completed heads will also be discussed. Aspects such a...
Article
Yoke type spin valve giant magnetoresistive (GMR) heads with a track width of 70 and 10 μm are studied. The head design has the sensor on top. The output of the heads is found to be up to 10 times larger than similar heads with a 30 nm Ni-Fe MRE linearized using a barberpole. The crucial role of the free layer permeability μ<sub>r </sub> and the fe...
Article
We studied the applicability of Ni<sub>80</sub>Fe<sub>20</sub>/Cu/Ni<sub>80</sub>Fe<sub>20</sub>/Fe <sub>50</sub>Mn<sub>50</sub> GMR multilayers for thin film tape heads. A method involving crossed anisotropies is applied for avoiding noise in the GMR response. We compare and analyse the sensitivities of AMR and GMR heads
Article
The digital compact cassette (DCC) system requires a multitrack recording head which can handle the digital multitrack format but can also playback standard analog compact cassette tapes. The layout and design of a recently developed thin film DCC head are discussed. An analysis of design parameters is presented, which shows why a small throat heig...

Citations

... Therefore, magneto-resistive sensor in pickup elements for string instruments, in particular for electric guitars, is a very promising area. A commercial AMR sensor ~Philips KMZ10 [6] were used as pickup element in [7], results an oscillating electronic output signal. Here, the vibration of the string modulates the magnetic field at the location of the MR sensor, which may be affected due to nearby wire fields or external fields. ...
... An alternative is the use of FIB trimmed state-of-the-art yoke-type magnetoresistive tape heads (YMRH) as SMRM sensors. These heads are similar to those developed by Philips in the mid-1990s for consumer applications in digital compact cassette (DCC) audio tape drives and advanced digital recording (ADR) tape streamers [9]- [11]. Although DCC was not a commercial success, YMRH heads were developed further and applied in the ADR system commercialized by OnStream. ...
... Mainly the motor speed is highly needed for control and drive systems [1][2][3]. Mostly the contactless speed measurement in the industry is based on electromagnetic sensors either by using electromagnetic induction, or Hall Effect or the magnetoresistive effect [4][5][6][7][8][9]. ...
... When the materials are fabricated into a sensing element and applied in an external field along the hard magnetization axis, the magnetic moment in the NiFe layer does not consistently rotate. This results in magnetic instability in the voltage output transfer curve of the sensing element [13]. At present, good magnetic stability is achieved mainly through complicated micromachining processes during the manufacture of a sensor, which considerably increases production cost. ...
... Here, we report an improvement in the magnetoresistance (MR) ratio of a spin-valve structure of Ta/NiFe/ CoFe/Cu/Ni/IrMn/Ta on a PI substrate, where NiFe and Ni layers are the free and pinned layers, respectively, by stress application, induced by controlled bending of the flexible layers, without post annealing processing. The MR ratio for a conventional spin-valve of Ni and permalloy on a silicon substrate shows relatively low values of ≈2~3% even if an adjacent antiferromagnetic layer is used for exchange bias with the pinned ferromagnetic layer [30][31][32] . However, we realized a significantly high MR ratio of 7% by applying a bending stress, which led to enhanced magnetic anisotropy due to an inverse magnetostriction effect. ...