A magnetoresistive read head includes a spin valve having at least one free layer spaced apart from at least one pinned layer by a spacer. The free layer includes a cobalt compound as a thin film including at least one of Co--X, CoFe--X and CoNi--X, where X is an element from the lanthanoid family (a 4-f element). The content of Co is higher than 80 percent, and the content of the lanthanoid element is less than 10 percent. The film may comprise the entire free layer, or be positioned adjacent to one or more conventional free layer films. The pinned layer is a conventional single layer, or a synthetic multi-layered structure having a spacer between sub-layers. Because the spin valve structure has a high exchange stiffness and damping factor, spin transfer effect is reduced and a high-speed dynamic response is provided.