Nickel is crucial for Earth’s magnetic field

Earth’s hot core, consisting mainly of iron, is responsible for the ‘dynamo effect,’ which creates a magnetic field. But with iron alone, this effect cannot be explained. A team of researchers has shown that the theory of the geodynamo has to be revised. It is crucial for the dynamo effect that the earth’s core contains up to 20 percent nickel — a metal, which under extreme conditions behaves quite differently from iron.
Geology News — ScienceDaily