Proceedings of the 2014 37th International Spring Seminar on Electronics Technology, 2014
ABSTRACT We realized ultra-thin and flexible magnetic field sensors based on the Hall Effect in 2... more ABSTRACT We realized ultra-thin and flexible magnetic field sensors based on the Hall Effect in 2 μm thick Bismuth films prepared on commercial flexible double-layer polyimide PCB with a total thickness of 150 μm. These sensors could be potentially applied in active magnetic bearing (AMB) systems. Therefore, here we address reliability aspects of flexible Hall sensors with emphasis on the proper choice of adhesive to mount the sensor to a stator of the AMB. The thermal shock tests in the standard automotive temperature range of -40°C to 165°C as well as the vibration test of the sensor mounted to the stator has proven the sensor's stability.
The inside front cover highlights the breakthrough from rigid silicon-based magnetoelectronic dev... more The inside front cover highlights the breakthrough from rigid silicon-based magnetoelectronic devices to soft and compliant ones. On page 1333, M. Melzer, D. Makarov, and co-workers describe a method to transfer entire magnetoresistive microsensor structures from a rigid silicon substrate to a pre-stretched rubber membrane in a single step. This fabrication route overcomes several limitations of previous approaches to compliant magnetoelectronics and allows for invariance versus stretching up to 30%.
ABSTRACT Stretchable magneto-resistive sensing elements have been introduced lately as a novel co... more ABSTRACT Stretchable magneto-resistive sensing elements have been introduced lately as a novel component providing magnetic functionality to stretchable consumer electronics involving smart skin or medical diagnostic applications. While spin valves already revealed high stretchability and reliability, GMR multilayers still lack mechanical compliance and production yield. Here, we report on two crucial improvements in fabrication of GMR multilayers to address these limiting issues. On the one hand, we increase the stretchability of wrinkled magnetic nanomembranes on free-standing elastomer membranes by photolithographically structuring them into a meander pattern. The meander can be regarded as a 2D spring, which can accommodate tensile strains in addition to the apparent wrinkling. On the other hand, we highlight a self-healing effect of GMR multilayers, which occurs due to a thermally induced pre-strain in the elastic support. This causes the soft membrane to contract after the GMR elements are prepared on top and closes cracks often induced during fabrication. Relying on this feature we are able to restore the full GMR performance, even if the magneto-sensitive element initially appeared to be without electrical contact before contraction of the free-standing soft membrane.
ABSTRACT We fabricated Permalloy (Fe19Ni81) nanomembranes rolled-up into compact three-dimensiona... more ABSTRACT We fabricated Permalloy (Fe19Ni81) nanomembranes rolled-up into compact three-dimensional architectures and experimentally investigated their magnetic and magneto-electric responses. When a magnetic nanomembrane is rolled-up, an additional magnetostatic interaction between the multiple windings emerges. Such kind of magnetostatic interaction, unique to the rolled-up magnetic nanomembranes and not accessible in any other magnetic architecture, is addressed for the first time in this study. An important feature of rolled-up tubes with multiple windings is that the inner and outer windings are formed by a single magnetic sheet; the spin configuration therefore must be continuous. The magnetostatic interaction induces anti-parallel alignment of the spins within adjacent layers of a rolled-up nanomembrane. The interplay between the magnetostatic interaction due to geometrical transformation and the exchange coupling in the film results in a stabilization of stripe domain patterns.
A grand vision of realization of smart and compact multifunctional microfluidic devices for weara... more A grand vision of realization of smart and compact multifunctional microfluidic devices for wearable health monitoring, environment sensing and point-of-care tests emerged with the fast development of flexible electronics. As a vital component towards this vision, magnetic functionality in flexible fluidics is still missing although demanded by the broad utility of magnetic nanoparticles in medicine and biology. Here, we demonstrate the first flexible microfluidic analytic device with integrated high-performance giant magnetoresistive (GMR) sensors. This device can be bent to a radius of 2 mm while still retaining its full performance. Various dimensions of magnetic emulsion droplets can be probed with high precision using a limit of detection of 0.5 pl, providing broad applicability in high-throughput droplet screening, flow cytometry and drug development. The flexible feature of this analytic device holds great promise in the realization of wearable, implantable multifunctional platforms for biomedical, pharmaceutical and chemical applications.
A novel fabrication method for stretchable magnetoresistive sensors is introduced, which allows t... more A novel fabrication method for stretchable magnetoresistive sensors is introduced, which allows the transfer of a complex microsensor systems prepared on common rigid donor substrates to prestretched elastomeric membranes in a single step. This direct transfer printing method boosts the fabrication potential of stretchable magnetoelectronics in terms of miniaturization and level of complexity, and provides strain-invariant sensors up to 30% tensile deformation.
Highly flexible bismuth Hall sensors on polymeric foils are fabricated, and the key optimization ... more Highly flexible bismuth Hall sensors on polymeric foils are fabricated, and the key optimization steps that are required to boost their sensitivity to the bulk value are identified. The sensor can be bent around the wrist or positioned on the finger to realize an interactive pointing device for wearable electronics. Furthermore, this technology is of great interest for the rapidly developing market of -eMobility, for optimization of eMotors and magnetic bearings.
A flexible light weight diagnostic platform is realized on cost-efficient large-area flexible foi... more A flexible light weight diagnostic platform is realized on cost-efficient large-area flexible foils enabling its cost-efficient high-volume delivery to medical institutions worldwide. The devices presented by L. Baraban, D. Makarov, and team on page 1517 allow the timely diagnosis of viral or infectious diseases, for example, the here demonstrated H1N1 subtype of the Avian Influenza Virus.
Proceedings of the 2014 37th International Spring Seminar on Electronics Technology, 2014
ABSTRACT We realized ultra-thin and flexible magnetic field sensors based on the Hall Effect in 2... more ABSTRACT We realized ultra-thin and flexible magnetic field sensors based on the Hall Effect in 2 μm thick Bismuth films prepared on commercial flexible double-layer polyimide PCB with a total thickness of 150 μm. These sensors could be potentially applied in active magnetic bearing (AMB) systems. Therefore, here we address reliability aspects of flexible Hall sensors with emphasis on the proper choice of adhesive to mount the sensor to a stator of the AMB. The thermal shock tests in the standard automotive temperature range of -40°C to 165°C as well as the vibration test of the sensor mounted to the stator has proven the sensor's stability.
The inside front cover highlights the breakthrough from rigid silicon-based magnetoelectronic dev... more The inside front cover highlights the breakthrough from rigid silicon-based magnetoelectronic devices to soft and compliant ones. On page 1333, M. Melzer, D. Makarov, and co-workers describe a method to transfer entire magnetoresistive microsensor structures from a rigid silicon substrate to a pre-stretched rubber membrane in a single step. This fabrication route overcomes several limitations of previous approaches to compliant magnetoelectronics and allows for invariance versus stretching up to 30%.
ABSTRACT Stretchable magneto-resistive sensing elements have been introduced lately as a novel co... more ABSTRACT Stretchable magneto-resistive sensing elements have been introduced lately as a novel component providing magnetic functionality to stretchable consumer electronics involving smart skin or medical diagnostic applications. While spin valves already revealed high stretchability and reliability, GMR multilayers still lack mechanical compliance and production yield. Here, we report on two crucial improvements in fabrication of GMR multilayers to address these limiting issues. On the one hand, we increase the stretchability of wrinkled magnetic nanomembranes on free-standing elastomer membranes by photolithographically structuring them into a meander pattern. The meander can be regarded as a 2D spring, which can accommodate tensile strains in addition to the apparent wrinkling. On the other hand, we highlight a self-healing effect of GMR multilayers, which occurs due to a thermally induced pre-strain in the elastic support. This causes the soft membrane to contract after the GMR elements are prepared on top and closes cracks often induced during fabrication. Relying on this feature we are able to restore the full GMR performance, even if the magneto-sensitive element initially appeared to be without electrical contact before contraction of the free-standing soft membrane.
ABSTRACT We fabricated Permalloy (Fe19Ni81) nanomembranes rolled-up into compact three-dimensiona... more ABSTRACT We fabricated Permalloy (Fe19Ni81) nanomembranes rolled-up into compact three-dimensional architectures and experimentally investigated their magnetic and magneto-electric responses. When a magnetic nanomembrane is rolled-up, an additional magnetostatic interaction between the multiple windings emerges. Such kind of magnetostatic interaction, unique to the rolled-up magnetic nanomembranes and not accessible in any other magnetic architecture, is addressed for the first time in this study. An important feature of rolled-up tubes with multiple windings is that the inner and outer windings are formed by a single magnetic sheet; the spin configuration therefore must be continuous. The magnetostatic interaction induces anti-parallel alignment of the spins within adjacent layers of a rolled-up nanomembrane. The interplay between the magnetostatic interaction due to geometrical transformation and the exchange coupling in the film results in a stabilization of stripe domain patterns.
A grand vision of realization of smart and compact multifunctional microfluidic devices for weara... more A grand vision of realization of smart and compact multifunctional microfluidic devices for wearable health monitoring, environment sensing and point-of-care tests emerged with the fast development of flexible electronics. As a vital component towards this vision, magnetic functionality in flexible fluidics is still missing although demanded by the broad utility of magnetic nanoparticles in medicine and biology. Here, we demonstrate the first flexible microfluidic analytic device with integrated high-performance giant magnetoresistive (GMR) sensors. This device can be bent to a radius of 2 mm while still retaining its full performance. Various dimensions of magnetic emulsion droplets can be probed with high precision using a limit of detection of 0.5 pl, providing broad applicability in high-throughput droplet screening, flow cytometry and drug development. The flexible feature of this analytic device holds great promise in the realization of wearable, implantable multifunctional platforms for biomedical, pharmaceutical and chemical applications.
A novel fabrication method for stretchable magnetoresistive sensors is introduced, which allows t... more A novel fabrication method for stretchable magnetoresistive sensors is introduced, which allows the transfer of a complex microsensor systems prepared on common rigid donor substrates to prestretched elastomeric membranes in a single step. This direct transfer printing method boosts the fabrication potential of stretchable magnetoelectronics in terms of miniaturization and level of complexity, and provides strain-invariant sensors up to 30% tensile deformation.
Highly flexible bismuth Hall sensors on polymeric foils are fabricated, and the key optimization ... more Highly flexible bismuth Hall sensors on polymeric foils are fabricated, and the key optimization steps that are required to boost their sensitivity to the bulk value are identified. The sensor can be bent around the wrist or positioned on the finger to realize an interactive pointing device for wearable electronics. Furthermore, this technology is of great interest for the rapidly developing market of -eMobility, for optimization of eMotors and magnetic bearings.
A flexible light weight diagnostic platform is realized on cost-efficient large-area flexible foi... more A flexible light weight diagnostic platform is realized on cost-efficient large-area flexible foils enabling its cost-efficient high-volume delivery to medical institutions worldwide. The devices presented by L. Baraban, D. Makarov, and team on page 1517 allow the timely diagnosis of viral or infectious diseases, for example, the here demonstrated H1N1 subtype of the Avian Influenza Virus.
Uploads
Papers by Michael Melzer