Spell 'magnetism' (5)
I believe the answer is:
charm
I believe this clue is a double definition.
'spell' is the first definition.
(a charm is a magic spell)
'magnetism' is the second definition.
(I've seen this in another clue)
(Other definitions for charm that I've seen before include "Engaging quality" , "Entrance; amulet" , "Spell; ornament" , "Enchant" , "Personal attractiveness and charisma" .)