This happens when the ferro-magnetic material is placed near to the magnet. (call this induced magnetism)
if the bar shape ferro-magnetic material's length is compressed into as thin as a sheet of iron,
Electromagnetic shielding occurs.
In the first situation, an iron pin will be attracted by the induced iron, but in the second situation, the iron pin will not be attracted.
I do not understand why will there be two occcurance, and how to classify any situation to know which will occur.