Schottky defect

Imagine a big box of Legos. Each Lego brick represents an atom in a crystal lattice. In this crystal of Legos, some of the spots where the bricks should connect are empty. That's called a "defect."

Schottky defect is when two atoms in the crystal lattice are missing, and as a result, there are two empty spots where atoms should be. It's like having two missing Lego bricks in a row.

The Schottky defect usually occurs in ionic compounds. In these compounds, there are positively charged and negatively charged atoms, and they are arranged in a regular order. If two atoms of opposite charges (one positive, one negative) are missing, then there will be two empty spots in the crystal lattice.

This type of defect can affect the properties of the material. For example, it may cause the crystal to conduct electricity differently or change its optical properties. But it can also make the crystal less stable, so it's not always a good thing.

Overall, Schottky defect is just a fancy name for a missing atom or two in the crystal structure. It's like having a few missing Legos in a row, which can affect how the block structure behaves.