400Hz Common mode toroid

Hello Santhibhusan, 

Thank you for your interest in TI products. 

This forum is intended for help and advice for using TI power management controllers and related control devices. 
It is not intended for general power supply advice.

That said, I can point you in the right direction.
For a common-mode filter inductor, a high-permeability ferrite core is most appropriate since the intent is to have as high a common-mode inductance as possible (within cost and size constraints). 

Iron powder cores are more suitable for differential-mode inductors, where low-permeability is required to sustain the high flux density of the winding current.  

I suggest to read the application notes and technical literature on these cores and applications available from Micrometals, Inc and Magnetics, Inc (among others). 
They can help you a lot more that we can on these topics. 

Regards, 
Ulrich