The Coriolis force, resulting from the Earth's spin. The flow of liquid iron generates electric currents, which in turn produce magnetic fields
No. The earth's magnetic field varies a lot in strength and direction, in different places and at different times. The magnetic north is moving nearly all the time, for instance.
Dear Sham Singh:
I am not sure at what type of material you need, or to what use you put it.
The greatest information on the Earth's internal magnetic field are the IGRF (International Geomagnetic Reference Field): http://fdd.gsfc.nasa.gov/IGRF.html
But, following your question, let me remember that the magnetism of the Earth does not arise from the fact that it is "Coriolis force, flow of liquid iron generates electric currents", although the rotation has an important role. Nor is it essential that the Earth's Coriolis force, Earth´s core seems to be mostly iron.
So, Earth and other planets in our Solar System must satisfy a conditions to have magnetic field:
1- The most important idea, the most imperative is that the Earth's core is metal, since metals conduct electricity. Also,
2- This metal is molten, and consequently can flow.
So,
3- This flow, which interacts in a complex way creates the magnetism as a by-product. Due that the fact that this flows can fluctuate, this also explains why the magnetic field of Earth is gradually changing (the main "bar magnet" lines S-N is fading 3-6% / century) and has in the past even reversed.
As Geophysicists, we try to remove or minimize the influence of the external field to keep the effect coming from sources in the Earth's crust. Despite all the variations, we have a great ally: the extraordinary relative contrasts in magnetic properties between the sediments and the basement, which gives confidence to the interpretations to estimate the geometry of the subsurface.
Best wishes, Mario
A neutral point is a point where the resultant magnetic field is zero. At the point marked X in figure, the earth's magnetic field and the magnet's field are exactly equal and opposite and the resultant field is zero. These points are called the neutral points.