Dear Student,
The material which is suitable for electromagnet is soft iron this is because soft iron has the property of losing its magnetism or we can say it is able to be demagnetized very quickly. Whereas steel does not lose all its magnetism when the current is stopped and it becomes a permanent magnet. An electromagnet works in the way when current flows through it, it becomes magnetized, and immediately current stops flowing, it loses its magnetism. Hence, soft iron cores are the ideal material for electromagnet. Regards