Stretchable Magnetoelectronics

Research on non-rigid electronics started almost 20 years ago originally motivated by an interest in flexible, paper-like displays [Gus92, Rog01]. There are several ways to achieve non-rigid electronics [Kim10-1]. One is related to the development of organic electronics [Sek10], which is flexible but slow. A good alternative to this approach are stretchable inorganic electronics, which combine advantages of being flexible with the speed and performance of conventional semiconductor-based electronics [Cav10]. Since being first introduced, stretchable electronics have become a dynamically developing research area which is of strong application interest due to the possibility to reshape the functional element on demand after its fabrication (Figure 1). There are already a variety of stretchable devices commercially available, i.e. electronic displays [Rog01, Chu09] and integrated circuitry [Kel04] to name a few. Until recently, the main focus was on fabrication of stretchable high-speed electronics [Kim11] and optoelectronics [Kim10] (Figure 1). However, the family of shapeable electronics is not limited to these two members. Only very recently, we reported for the first time the fabrication of stretchable magnetoelectronics [Mel11, Mel12, Mel12-1]. These stretchable magnetoelectronics pave the way towards the development of a unique class of devices with important functionality being not only stretchable and fast, but also with the ability to react and respond to a magnetic field.

Figure 1: Family of shapeable electronics: (Top panel) Opto-electronics [Kim10]: array of light emitting diodes (LEDs). (Bottom left) Electronics [Kim11]: Multifunctional inflatable balloon catheters. (Bottom right) New member of the family - shapeable magneto-electronics: a giant magneto-resistive (GMR) sensor element on a free-standing rubber membrane. The shapeability of the magnetic sensor element is due to the wrinkle formation. The figure is taken from [Mel11].

Layered magnetic structures revealing a giant magnetoresistance (GMR) effect are crucial components of highly sensitive magnetic sensor devices. We fabricated [Co/Cu] and [Py/Cu] GMR multilayers [Mel11, Mel12] as well as spin valve systems [Mel12-1] on free-standing elastic Poly(dimethylsiloxane) (PDMS) membranes. The GMR performance of GMR sensors on rigid silicon and on free-standing PDMS is similar and does not change with tensile deformations of up to 29% revealing a top sensitivity of 0.8 %/Oe in the magnetic field of 12 Oe [Mel12-1]. These highly stretchable and highly sensitive elements responding to a magnetic field are demanded for novel application fields like smart skin, flexible and stretchable consumer electronics equipped with magnetic functionalities.

References:
[Gus92] G. Gustafsson et al., Nature 357, 477 (1992).
[Rog01] J. A. Rogers et al., PNAS 98, 4835 (2001).
[Kim10-1] D. H. Kim et al., Adv. Mater. 22, 2108 (2010).
[Sek10] T. Sekitani et al., Adv. Mater. 22, 2228 (2010).
[Cav10] F. Cavallo et al., Soft Matter 6, 439 (2010).
[Chu09] I. J. Chung et al., Molecular Crystals and Liquid Crystals 507, 1 (2009).
[Kel04] T. W. Kelley et al., Chemistry of Materials 16, 4413 (2004).
[Kim10] R. H. Kim et al., Nature Mater. 9, 929 (2010).
[Kim11] D. H. Kim et al., Nature Mater. 10, 316 (2011).
[Mel11] M. Melzer et al., Nano Letters 11, 2522 (2011).
[Mel12] M. Melzer et al., RSC Adv. 2, 2284 (2012).
[Mel12-1] M. Melzer et al., Adv. Mater. 24, 6468 (2012).




This project has received funding from the European Union’s Seventh Framework Programme for research, technological development and demonstration
under grant agreement no 306277.