What is a Piezoelectricity? | Piezoelectricity vs Ferroelectricity

How can we harvest energy using piezoelectric?

Piezoelectricity: A method to harvest renewable energy

According to EIA (Energy Information Administration), Economic growth leads to an increment in energy demand. Energy demand rises as economies expand, and if energy supplies are limited, GDP growth also slows. That has been the situation at least since the beginning of the Industrial Revolution.

Conventional energy sources are being replaced by renewable energy to fulfill our demand without depending on fuels which soon will deplete. Many energy sources that could be renewed are being used in day-to-day life to meet the requirement such as solar energy, biomass energy, wind energy, etc. Many other methods are being introduced to accomplish energy requirements. One such method of renewable is piezoelectricity.

The Curie brothers, Pierre and Jacques, made the initial discovery of the direct piezoelectric effect more than a century ago. They discovered that electrical charges developed when mechanical tension was applied to crystals including topaz, tourmaline, Rochelle salt, quartz, and cane sugar, (also known as piezoelectric materials) and that this voltage was proportional to the stress.

Piezoelectric materials produce an electric charge when they are subjected to a mechanical load.  Usually, this phenomenon is referred to as the “Piezoelectric effect“. In contrast, piezoelectric material experiences dimensional changes when electrically strained by a voltage “Inverse piezoelectric effect” is the term used to describe this phenomenon.

The electric fields that go along with piezoelectric stresses are enormous. A field of 1000 V/cm creates a strain on the order of in quartz, for instance. On the other hand, tiny strains can result in big electric fields.

Electromagnetic induction, and electrostatic induction, are some of the techniques used to transform mechanical energy from vibrating or moving objects into electrical energy required by electronic systems apart from the piezoelectric effect.

Due to its greater flexibility and higher energy density of system integration when compared to electromagnetic and electrostatic techniques, energy harvesting with piezoelectric materials has attracted the most attention.

Piezoelectricity is used in cellular phones, diesel fuel injectors, ultrasonic transducers, grill igniters, vibration sensors, acoustic guitar pickups, some printers, musical greeting cards, etc. the continued development of artificial piezo materials, such as piezoelectric ceramics.

The following fields are among the ones where piezoelectricity is used:

  • Piezoelectric motors,
  • industrial actuators,
  • medical sensors,
  • actuators for consumer electronics (Printers, Speakers)
  • Nanopositioning in AFM, STM,
  • Micro Robotics (Defense),
  • Piezoelectric Buzzers,
  • Instrument Pick-Ups,
  • Microphones,
  • Piezoelectric Igniters

Ferroelectricity is a property of some materials that can have their spontaneous electric polarisation reversed when an external electric field is applied. All ferroelectric materials are pyroelectric, and they also have reversible natural electrical polarization. The word is used as a comparison to ferromagnetism, in which a fabric displays a magnet’s permanent moment.

When Valasek found ferroelectricity in Rochelle salt in 1920, ferromagnetism was already well-known. Thus, despite the fact that the majority of ferroelectric materials don’t include iron, the prefix Ferro, which means iron, was chosen to define the attribute.

Multiferroics are substances that have both ferromagnetic and ferroelectric properties. Due to their switchable polarisation, and outstanding pyroelectric capabilities, ferroelectric materials can be employed to generate energy for low-power electronic systems.

Piezoelectricity Vs Ferroelectricity

 What is the difference between piezoelectric and ferroelectric?

Let’s compare both,

  1. In ferroelectricity, the source of polarization is the dipole interaction energy itself, but in piezoelectricity, the crystal is polarised by the application of external stress.
  2. There are 20 different types of noncentrosymmetric crystals where both events take place. All 20 crystals exhibit piezoelectricity, while only 10 of them, specifically those that offer a suitable axis of polarity, exhibit ferroelectricity.
  3. Since all ferroelectrics are also piezoelectric, not all piezoelectric materials are ferroelectric. For instance, tourmaline is both piezoelectric and completely non-ferroelectric.
  4. The setup charge to the tension put on a crystallographic axis is expressed as the piezoelectric coefficient. The piezoelectric coefficients of the ferroelectrics are extremely high.

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