Context
A new study by an international team of researchers along with those from the Indian Institute of Science (IISc), has unveiled an unusual form of ferroelectricity rise in certain nano-sized materials.
About the Study
- Experiment: The state-of-the-art atomic resolution microscopy was used to do the experiment.
- It was the first time that directly imaging of the dynamics of light elements was done using electron microscopy.
- Material used: The hafnia-based oxides were used during the experiment.
- These materials are useful for low-power memory applications and are already in production.
- It was observed that when an electric field is applied in materials called hafnia-based oxides, the ferroelectricity arises.
- It may have arisen because of the displacement and reversible movement of negatively charged oxygen atoms.
Hafnium
- It is a chemical element having symbol Hf and atomic number 72.
- It is a lustrous, silvery gray, tetravalent transition metal.
- Hafnium chemically resembles zirconium and is found in many zirconium minerals.
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- Ferroelectric material are generally unsuitable for miniaturisation as they lose their ferroelectric properties when the crystal is made smaller than a particular size.
- Hafnia-based oxides provide an alternative for this as they could exhibit ferroelectricity even when they are nano-sized.
- Their ferroelectricity even grows stronger as the material size gets smaller that opens up numerous opportunities for microelectronics.
Findings of the Study
- In the new study, the researchers imagine the thin films of hafnium-zirconium oxide sandwiched between two electrodes.
- The movement of atoms of oxygen was observed in real time when an electric field was applied.
- The charged oxygen atoms move from one electrode to another with the hafnia layer acting as a conduit.
- Reversing the electric field also reverses the direction of migration was also reversed.
- Due to the migration of Oxygen atom the materials got ferroelectricity.
- When the conduit size was reduced (as the device is made smaller), oxygen conduction became more robust.
- These findings were also confirmed by X-ray diffraction studies carried out in Sweden.
