Magnetic head and magnetic recording device

A magnetic head, comprising:

• a first magnetic pole;
• a second magnetic pole;
• a stacked body provided between the first magnetic pole and the second magnetic pole, the stacked body including:
• a first magnetic layer,
• a second magnetic layer provided between the first magnetic layer and the second magnetic pole,
• a third magnetic layer provided between the second magnetic layer and the second magnetic pole,
• a fourth magnetic layer provided between the third magnetic layer and the second magnetic pole,
• a first nonmagnetic layer provided between the first magnetic pole and the first magnetic layer,
• a second nonmagnetic layer provided between the first magnetic layer and the second magnetic layer and being in contact with the first magnetic layer and the second magnetic layer,
• a third nonmagnetic layer provided between the second magnetic layer and the third magnetic layer,
• a fourth nonmagnetic layer provided between the third magnetic layer and the fourth magnetic layer and being in contact with the third magnetic layer and the fourth magnetic layer, and
• a fifth nonmagnetic layer provided between the fourth magnetic layer and the second magnetic pole;
• a first terminal electrically connected to the first magnetic pole;
• a second terminal electrically connected to the second magnetic pole;
• and
• a third terminal electrically connected to the third nonmagnetic layer,
• wherein
• a first thickness of the first magnetic layer along a first direction from the first magnetic layer to the fourth magnetic layer is thicker than a second thickness of the second magnetic layer along the first direction, and thicker than a third thickness of the third magnetic layer along the first direction, and
• a fourth thickness of the fourth magnetic layer along the first direction is thicker than the second thickness and thicker than the third thickness.

A magnetic head, comprising:

• a first magnetic pole;
• a second magnetic pole;
• a stacked body provided between the first magnetic pole and the second magnetic pole, the stacked body including:
• a first magnetic layer,
• a second magnetic layer provided between the first magnetic layer and the second magnetic pole,
• a third magnetic layer provided between the second magnetic layer and the second magnetic pole,
• a fourth magnetic layer provided between the third magnetic layer and the second magnetic pole,
• a first nonmagnetic layer provided between the first magnetic pole and the first magnetic layer,
• a second nonmagnetic layer provided between the first magnetic layer and the second magnetic layer and being in contact with the first magnetic layer and the second magnetic layer,
• a third nonmagnetic layer provided between the second magnetic layer and the third magnetic layer,
• a fourth nonmagnetic layer provided between the third magnetic layer and the fourth magnetic layer and being in contact with the third magnetic layer and the fourth magnetic layer, and
• a fifth nonmagnetic layer provided between the fourth magnetic layer and the second magnetic pole;
• a first terminal electrically connected to the first magnetic pole;
• a second terminal electrically connected to the second magnetic pole;
• and
• a third terminal electrically connected to the third nonmagnetic layer,
• wherein a length of the third nonmagnetic layer along a crossing direction crossing a facing direction from the third nonmagnetic layer to the fourth magnetic layer is longer than a length of the second magnetic layer along the crossing direction, and longer than a length of the third magnetic layer along the crossing direction.