Magnetoresistive element and magnetic memory

A magnetoresistive element comprising:

• a first magnetic layer;
• a second magnetic layer;
• a nonmagnetic layer disposed between the first magnetic layer and the second magnetic layer;
• a first layer including:
• at least one element selected from a first group consisting of Hf, Zr, Al, Cr, and Mg;
• and at least one element selected from a second group consisting of Ta, W, Nb, Ge, Be, Li, Sn, Sb, and P, the second magnetic layer being disposed between the first layer and the first magnetic layer;
• a second layer including at least one element selected from a group consisting of Hf, Zr, Al, Cr, Ti, Sc, and Mg, the second layer being disposed between the first layer and the second magnetic layer;
• and
• an insulating layer disposed at least on a side surface of the nonmagnetic layer, the insulating layer including at least one element selected from the first group,
• wherein the first layer includes a first region and a second region disposed between the first region and the second magnetic layer, and the at least one element selected from the second group has a higher concentration in the second region than in the first region.

A magnetoresistive element comprising:

• a first layer;
• a first magnetic layer;
• a second magnetic layer disposed between the first layer and the first magnetic layer;
• a nonmagnetic layer disposed between the first magnetic layer and the second magnetic layer;
• and
• an insulating layer disposed on at least side surfaces of the nonmagnetic layer, wherein
• the first layer includes at least one of Hf, Zr, Al, Cr, or Mg;
• or at least one of Ru, Pt, Pd, W, or Ti,
• the second magnetic layer includes a third magnetic layer, a fourth magnetic layer disposed between the third magnetic layer and the nonmagnetic layer, and a second layer disposed between the third magnetic layer and the fourth magnetic layer,
• the third magnetic layer includes at least one of an alloy having a L10 structure containing Fe or MnGa, an artificial superlattice containing Co, CoCrPt, a MnGa alloy having a DO22 structure, or a rare earth magnetic compound,
• the second layer includes at least one of B, Zr, Hf, Ta, Nb, Mo, W, Ti, V, Cr, Mn, Ni, Cu, Ru, Ag, Mg, or a rare earth element,
• at least one of the third magnetic layer and the fourth magnetic layer includes at least one of Hf, Zr, Al, Cr, or Mg, and
• the insulating layer includes at least one of Hf, Zr, Al, Cr, or Mg.