it is the flux which is flowing opposite to the main field flux and demaganetize it...

in order to eliminate this demagnetiszing component we have to connect the compensating winding in series with the armature winding which develop the flux in it oppose to the demagnetizing component

Because lava can melt iron (demagnetizing it) and when it solidifies, it will pick up whatever magnet field it is currently subject to, thus locking in a record of the magnet field at the time in history.

The armature reaction is the interaction between armature flux and field flux when current is introduced to a dc motor. It results in a cross-magnetizing effect and a demagnetizing effect.

Demagnetizing a current means too take away the magnetism from the current ;)

The electrons will fall out of line, demagnetizing the nail.