A magneto-resistive effect (MR) element includes first and second magnetic layers in which a relative angle formed by magnetization directions changes responsive to an external magnetic field, and a spacer layer positioned between the first and second magnetic layers. The first magnetic layer is positioned closer to a substrate above which the MR element is formed than the second magnetic layer. The spacer layer includes copper and metal intermediate layers and a main spacer layer composed primarily of gallium oxide. The copper and metal intermediate layers are positioned between the main spacer and first magnetic layers. The metal intermediate layer is positioned between the copper and main spacer layers. The metal intermediate layer is composed primarily of at least one from a group of one of magnesium and at least partially oxidized magnesium, and one of aluminum and at least partially oxidized aluminum.