Provided is a magnetic tunnel junction element and a magnetoresistive memory device. The magnetic tunnel junction element includes a fixed layer maintaining a magnetization direction, an insulating layer, a free layer having a variable magnetization direction, and an antiferromagnetic oxide layer. The fixed layer, the free layer, and the antiferromagnetic oxide layer may be sequentially stacked. The free layer and the antiferromagnetic oxide layer may be in direct contact with each other.