Doctor musical material (6)
I believe the answer is:
mohair
'material' is the definition.
(mohair is a kind of material)
'doctor musical' is the wordplay.
'doctor' becomes 'mo' (medical officer).
'musical' becomes 'hair' (1960s musical).
'mo'+'hair'='MOHAIR'
(Other definitions for mohair that I've seen before include "Fibre got from goats" , "coat required" , "Fine silky wool of the angora goat" , "Fabric made from fine silky wool of goat" , "Goat's silky coating as material for shiny clothes" .)