Magnetic head with multilayer configuration between magnetic poles and magnetic recording device
According to one embodiment, a magnetic head includes a first magnetic pole, a second magnetic pole, and a magnetic element provided between the first and the second magnetic poles. The magnetic element includes first to fifth magnetic layers, and first to sixth non-magnetic layers. The sixth non-magnetic layer is provided between the fifth magnetic layer and the second magnetic pole. The sixth non-magnetic layer includes at least one selected from the group consisting of Ru, Ir, Ta, Rh, Pd, Pt and W.
1. A magnetic head, comprising:
a first magnetic pole;
a second magnetic pole; and
a magnetic element provided between the first magnetic pole and the second magnetic pole,
the magnetic element 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 fifth magnetic layer provided between the fourth magnetic layer and the second magnetic pole,
a first non-magnetic layer provided between the first magnetic pole and the first magnetic layer,
a second non-magnetic layer provided between the first magnetic layer and the second magnetic layer,
a third non-magnetic layer provided between the second magnetic layer and the third magnetic layer,
a fourth non-magnetic layer provided between the third magnetic layer and the fourth magnetic layer,
a fifth non-magnetic layer provided between the fourth magnetic layer and the fifth magnetic layer, and
a sixth non-magnetic layer provided between the fifth magnetic layer and the second magnetic pole,
the sixth non-magnetic layer including at least one selected from the group consisting of Ru, Ir, Ta, Rh, Pd, Pt and W,
wherein
the first non-magnetic layer includes at least one selected from the group consisting of Ru, Ir, Ta, Rh, Pd, Pt and W,
the fourth non-magnetic layer includes at least one selected from the group consisting of Ru, Ir, Ta, Rh, Pd, Pt and W,
the second non-magnetic layer includes at least one selected from the group consisting of Cu, Au, Cr, Al, V and Ag,
the third non-magnetic layer includes at least one selected from the group consisting of Cu, Au, Cr, Al, V and Ag,
the fifth non-magnetic layer includes at least one selected from the group consisting of Cu, Au, Cr, Al, V and Ag,
a second thickness of the second magnetic layer in a first direction from the first magnetic pole to the second magnetic pole is thicker than a first thickness of the first magnetic layer in the first direction,
the second thickness is thicker than a third thickness of the third magnetic layer in the first direction,
a fourth thickness of the fourth magnetic layer in the first direction is thinner than a fifth thickness of the fifth magnetic layer in the first direction,
the first magnetic layer directly contacts the first non-magnetic layer and the second non-magnetic layer,
the second magnetic layer directly contacts the second non-magnetic layer and the third non-magnetic layer,
the third magnetic layer directly contacts the third non-magnetic layer and the fourth non-magnetic layer,
the fourth magnetic layer directly contacts the fourth non-magnetic layer and the fifth non-magnetic layer, and
the fifth magnetic layer directly contacts the fifth non-magnetic layer and the sixth non-magnetic layer.
2. The magnetic head according to claim 1 , wherein
the first non-magnetic layer contacts the first magnetic pole and the first magnetic layer,
the second non-magnetic layer contacts the first magnetic layer and the second magnetic layer,
the third non-magnetic layer contacts the second magnetic layer and the third magnetic layer,
the fourth non-magnetic layer contacts the third magnetic layer and the fourth magnetic layer,
the fifth non-magnetic layer contacts the fourth magnetic layer and the fifth magnetic layer, and
the sixth non-magnetic layer contacts the fifth magnetic layer and the second magnetic pole.
3. A magnetic recording device, comprising:
the magnetic head according to claim 1 ; and
a controller including an element circuit,
one end of the magnetic element being electrically connected to the first magnetic pole,
another end of the magnetic element being electrically connected to the second magnetic pole, and
the element circuit being configured to apply an element voltage between the first magnetic pole and the second magnetic pole.
4. The magnetic recording device according to claim 3 , wherein
a differential electric resistance of the magnetic element when a voltage between the first magnetic pole and the second magnetic pole is changed includes a first peak, a second peak and a third peak,
when the voltage is positive, a potential of the first magnetic pole is lower than a potential of the second magnetic pole,
when the voltage is negative, the potential of the first magnetic pole is higher than the potential of the second magnetic pole,
the voltage corresponding to the first peak is a first voltage,
the voltage corresponding to the second peak is a second voltage,
the voltage corresponding to the third peak is a third voltage,
the second voltage is between the first voltage and the third voltage,
the element voltage satisfies one of a first condition, a second condition, a third condition and a fourth condition,
in the first condition, the first voltage is negative, the second voltage, the third voltage and the element voltage are positive, and the element voltage is equal to or higher than the third voltage,
in the second condition, the first voltage and the second voltage are negative, the third voltage and the element voltage are positive, and the element voltage is equal to or higher than the third voltage,
in the third condition, the first voltage and the element voltage are negative, the second voltage and the third voltage are positive, and the absolute value of the element voltage is equal to or greater than the absolute value of the first voltage, and
in the fourth condition, the first voltage, the second voltage, and the element voltage are negative, the third voltage is positive, and the absolute value of the element voltage is equal to or greater than the first voltage.
5. A magnetic head, comprising:
a first magnetic pole;
a second magnetic pole; and
a magnetic element provided between the first magnetic pole and the second magnetic pole,
the magnetic element 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 fifth magnetic layer provided between the fourth magnetic layer and the second magnetic pole,
a first non-magnetic layer provided between the first magnetic pole and the first magnetic layer,
a second non-magnetic layer provided between the first magnetic layer and the second magnetic layer,
a third non-magnetic layer provided between the second magnetic layer and the third magnetic layer,
a fourth non-magnetic layer provided between the third magnetic layer and the fourth magnetic layer,
a fifth non-magnetic layer provided between the fourth magnetic layer and the fifth magnetic layer, and
a sixth non-magnetic layer provided between the fifth magnetic layer and the second magnetic pole,
the sixth non-magnetic layer including at least one selected from the group consisting of Ru, Ir, Ta, Rh, Pd, Pt and W,
wherein
the first non-magnetic layer includes at least one selected from the group consisting of Ru, Ir, Ta, Rh, Pd, Pt and W,
the fourth non-magnetic layer includes at least one selected from the group consisting of Ru, Ir, Ta, Rh, Pd, Pt and W,
the second non-magnetic layer includes at least one selected from the group consisting of Cu, Au, Cr, Al, V and Ag,
the third non-magnetic layer includes at least one selected from the group consisting of Cu, Au, Cr, Al, V and Ag,
the fifth non-magnetic layer includes at least one selected from the group consisting of Cu, Au, Cr, Al, V and Ag,
a second thickness of the second magnetic layer in a first direction from the first magnetic pole to the second magnetic pole is thicker than a first thickness of the first magnetic layer in the first direction,
the second thickness is thicker than a third thickness of the third magnetic layer in the first direction,
the magnetic element further includes:
a sixth magnetic layer, and
a seventh non-magnetic layer,
the sixth magnetic layer is provided between the fifth magnetic layer and the sixth non-magnetic layer, and
the seventh non-magnetic layer is provided between the fifth magnetic layer and the sixth magnetic layer,
the seventh non-magnetic layer includes at least one selected from the group consisting of Cu, Au, Cr, Al, V and Ag,
a fifth thickness of the fifth magnetic layer in the first direction is thicker than a fourth thickness of the fourth magnetic layer in the first direction, and
the fifth thickness is thicker than a sixth thickness of the sixth magnetic layer in the first direction.
6. The magnetic head according to claim 5 , wherein
a fourth thickness of the fourth magnetic layer in the first direction is thinner than a fifth thickness of the fifth magnetic layer in the first direction.
7. The magnetic head according to claim 5 , wherein
the first non-magnetic layer contacts the first magnetic pole and the first magnetic layer,
the second non-magnetic layer contacts the first magnetic layer and the second magnetic layer,
the third non-magnetic layer contacts the second magnetic layer and the third magnetic layer,
the fourth non-magnetic layer contacts the third magnetic layer and the fourth magnetic layer,
the fifth non-magnetic layer contacts the fourth magnetic layer and the fifth magnetic layer,
the seventh non-magnetic layer contacts the fifth magnetic layer and the sixth magnetic layer, and
the sixth non-magnetic layer contacts the sixth magnetic layer and the second magnetic pole.
8. The magnetic head according to claim 5 , wherein
one end of the magnetic element is electrically connected to the first magnetic pole,
another end of the magnetic element is electrically connected to the second magnetic pole, and
a differential electrical resistance of the magnetic element when a voltage between the first magnetic pole and the second magnetic pole is changed includes 3 or more peaks.
9. A magnetic recording device, comprising:
the magnetic head according to claim 5 ; and
a controller including an element circuit,
one end of the magnetic element being electrically connected to the first magnetic pole,
another end of the magnetic element being electrically connected to the second magnetic pole, and
the element circuit being configured to apply an element voltage between the first magnetic pole and the second magnetic pole.
10. The magnetic recording device according to claim 9 , wherein
a differential electric resistance of the magnetic element when a voltage between the first magnetic pole and the second magnetic pole is changed includes a first negative peak, a second negative peak, a first positive peak and a second positive peak,
when the voltage is positive, a potential of the first magnetic pole is lower than a potential of the second magnetic pole,
when the voltage is negative, the potential of the first magnetic pole is higher than the potential of the second magnetic pole,
the voltage corresponding to the first negative peak is a first negative peak voltage being negative,
the voltage corresponding to the second negative peak is a second negative peak voltage being negative,
the voltage corresponding to the first positive peak is a first positive peak voltage being positive,
the voltage corresponding to the second positive peak is a second positive peak voltage being positive,
the second negative peak voltage is between the first negative peak voltage and the second positive peak voltage,
the first positive peak voltage is between the second negative peak voltage and the second positive peak voltage,
the element voltage satisfies one of a fifth condition and a sixth condition,
in the fifth condition, the element voltage is positive, the element voltage is equal to or higher than the second positive peak voltage, and
in the sixth condition, the element voltage is negative, and the absolute value of the element voltage is greater than or equal to the absolute value of the first negative peak voltage.