What kind of external microphone can I use with my Galaxy smartphone?
Consider a couple of products from Australian microphone maker Røde.


Røde VideoMic Me: http://en.rode.com/microphones/videomicme
Røde smartLav+: http://en.rode.com/microphones/smartlav-plus


Røde makes pretty high-quality products and are leaders in making new products like these mcicrophones which are designed to plug directly into the TRRS connectors of smartphones.

I have no connection with Røde except as a satisfied, paying customer.