BFO(Bismuth ferrite) is a good antiferromagnetic material with Neel temperature around 653K, so you can refer to its literature.

Gud luck

The metallic classic woud be FeRh, I think.

Thanks Dr. Fauth. We've already started the study of FeRh, anything else in your mind? 

Just came across this one. The temperature of interest is 150 K rather than 300 K, though. But following the leads of who they quote and whom they are quoted by might reveal new candidates ?!

http://www.sciencedirect.com/science/article/pii/0925838894014965

Thanks a lot Dr. Fauth.