Piezoelectric materials have long been valued for their ability to generate electricity when mechanically stressed. This unique property has led to their widespread use in sensors, medical devices, and energy-harvesting technology. But could these materials be controlled remotely using magnetic fields? Although, to our knowledge, no natural piezoelectric materials currently exhibit this capability, scientific research suggests that synthetic materials may be designed to do so. Advances in mathematical modelling and numerical simulations are bringing this possibility closer to reality.
The use of a magnetic field may be sufficient to stabilize a piezoelectric body around a desired shape. This possibility leads directly to the remote control of piezoelectric devices.
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How piezoelectricity powers modern technology
Piezoelectric materials deform when exposed to an electromagnetic field and generate an electric charge when subjected to mechanical stress. This phenomenon was first demonstrated in 1880 by Jacques and Pierre Curie. Over three decades later, Paul Langevin and his colleagues applied this principle in sonar technology, marking one of the first practical uses of piezoelectricity. Today, piezoelectric devices play a critical role in aerospace, automotive engineering, biomedical technology, and even everyday items such as electric lighters. These materials are used to control the shape of aircraft wings, measure stress in mechanical structures, and improve artificial organ performance.
Recent developments have focused on new applications, such as harvesting energy from pedestrian footsteps. Specialised floor tiles can convert kinetic energy into electricity, powering LED lights for short periods. According to research by Pavegen, a single footstep can generate enough energy to illuminate a light for 20 seconds. With thousands of steps taken daily, this technology has the potential to make a significant impact on sustainable urban development.
In urban infrastructure, piezoelectric sensors embedded in roads can monitor traffic flow and direction, offering valuable data for transport planning and safety management. At the same time, efforts continue to improve the durability of these systems. Since piezoelectric materials are naturally brittle, researchers are striving to enhance their longevity. Achieving this would make energy-harvesting roadways not only innovative but also economically viable.
The challenge of material fragility and ongoing improvements
One of the main challenges in piezoelectric technology is the brittleness of the materials. For widespread adoption in infrastructure, such as road traffic energy harvesting, these materials must be durable enough to match the lifespan of roads, which is typically between 15 and 20 years.
Scientists have made progress in strengthening piezoelectric materials by modifying their crystalline structures. This process, known as doping, introduces new atoms into the material. A well-known example is the modification of lead zirconate titanate ceramics, which were developed in 1952 and are widely used in transducers and actuators. More recently, researchers have explored samarium-doped piezoelectric materials, demonstrating their potential for enhanced performance in future applications.
Efforts are also being made to develop lead-free alternatives. While lead-based piezoelectric materials are highly effective, they pose environmental risks. Researchers are working on bio-compatible and eco-friendly options, such as potassium sodium niobate, which could be safer and more sustainable.
Mathematical models shaping the future
Mathematics plays a crucial role in advancing piezoelectric research. Mathematical models help predict how these materials behave under different conditions, guiding scientists in designing more effective applications. Since piezoelectric materials are often used as thin patches attached to surfaces, accurate modelling is necessary to ensure efficiency.
Researchers have developed several models to describe the behaviour of piezoelectric plates. One recent study examined how these materials could be optimised for use in biomedical implants. For instance, pacemakers currently rely on lithium batteries that require surgical replacement every seven years (Figure 1). Research into piezoelectric-powered implants suggests that future pacemakers could be powered by the natural movements of the human heart, eliminating the need for battery replacements.
Scientists are also using mathematical models to simulate how piezoelectric materials perform under extreme conditions, such as high pressure or rapid temperature changes. This knowledge is essential for applications in space exploration and deep-sea technology, where materials must function reliably under harsh environmental conditions.
Credit. Khazaee M et al, Micromachines, 2024
Can magnetic fields control motion?
Researchers are now exploring whether piezoelectric materials can be controlled remotely using magnetic fields. This concept involves converting magnetic energy into mechanical motion, allowing external forces to influence the shape and behaviour of these materials.
A recent study investigated whether magnetic fields could stabilise vibrating piezoelectric bodies. By applying mathematical equations to estimate vibration energy, researchers successfully demonstrated that a magnetic field could bring a vibrating body to rest. This means that remote control of piezoelectric materials using a magnetic field may be possible without the need for direct physical contact.
To achieve this, scientists developed control laws based on factors such as internal electric charge density and surface current density. Their findings suggest that using a magnetic field alone may be enough to regulate the motion of these materials. This breakthrough opens up possibilities for remotely controlled devices in fields such as robotics, medicine, and aerospace engineering.
In medicine, the ability to manipulate tiny piezoelectric elements using a magnetic field could lead to major advancements in targeted drug delivery. Microscopic robots equipped with piezoelectric actuators could be guided to specific areas of the body, releasing medication with precise control. This could improve treatments for conditions such as cancer, where targeted therapy is crucial to minimising side effects.
What’s next for piezoelectric innovation?
Although research has confirmed the feasibility of controlling piezoelectric materials with a magnetic field, further work is needed to refine the process. Scientists are exploring ways to optimise control laws and improve efficiency for a wider range of materials. Another important area of research involves the development of two-dimensional models of piezoelectric thin films, which could lead to lightweight and flexible applications in wearable technology and bioelectronics.
The implications of these findings extend beyond scientific theory. If piezoelectric materials can be manipulated remotely, new possibilities emerge for smart implants that adjust themselves within the human body, aircraft components that change shape mid-flight, or self-healing materials that respond to environmental changes.
Future advancements in this field could also play a role in space exploration. Piezoelectric actuators that respond to magnetic fields may help build self-adjusting spacecraft structures that adapt to changing conditions in outer space. This could reduce maintenance needs and improve the longevity of deep-space missions.
The future of piezoelectricity is still unfolding. With ongoing research, could we soon see everyday objects that move and adapt using nothing but a magnetic field? The potential applications are vast, and the possibilities are only just beginning to be explored.
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Journal reference
Bidouan, R., Sène, A., & Marcos, A. (2024). Exponential stabilisation of piezoelectric materials via an electromagnetic field. International Journal of Control, 1-13. https://doi.org/10.1080/00207179.2024.2423873
