A magnetoresistive sensor includes a first non-magnetic layer, a second non-magnetic layer, and a magnetic free bi-layer. The magnetic free bi-layer is disposed between first non-magnetic layer and the second non-magnetic layer, the magnetic free bi-layer including a first magnetic free layer coupled to a second magnetic free layer. The first magnetic free layer is coupled to the first non-magnetic layer, and the second magnetic free layer is coupled to the second non-magnetic layer. The second non-magnetic layer comprises a non-magnetic material having an atomic radius within 10% of an atomic radius of at least one of the first magnetic free layer and the second magnetic free layer.