**4.1.2 Electrical properties**

Four-point (or five-point) probe methods are often applied either to ingots, crystals or pressed pellets to measure resistivity and the size of the Hall effect. This gives information on whether the compound is an insulator, semiconductor, semimetal or metal and upon the type of doping and the mobility in the delocalized bands (if present). Thus, important information is obtained on the chemical bonding in the material.

The impedance spectroscopy is also a very useful method used for electrical properties characterization of perovskite-type materials, especially for bulk ceramic samples.
