The present disclosure provides a semiconductor memory device. The device includes a bottom electrode over a semiconductor substrate; an anti-ferromagnetic layer disposed over the bottom electrode; a pinned layer disposed over the anti-ferromagnetic layer; a barrier layer disposed over the pinned layer; a first ferromagnetic layer disposed over the barrier layer; a buffer layer disposed over the first ferromagnetic layer, the buffer layer including tantalum; a second ferromagnetic layer disposed over the buffer layer; and a top electrode disposed over the second ferromagnetic layer.