My understanding is that Zakat is only to be given for Muslims. Can it also be given to non-Muslim who is in poverty?
Nope unless they are in the process of or close to embracing Islam.
Charity on the other hand, can be given to non Muslims if they are not in a state of war with Muslims or are not doing injustice to Muslims or driving them out of their land. However, it's still better to give charity to Muslims only.
For more information regarding this topic, please refer to the following link.