US 9,230,571 B1Granted

MgO based perpendicular spin polarizer in microwave assisted magnetic recording (MAMR) applications

AssigneeHeadway Technologies, Inc.

InventorsWenyu Chen, Yan Wu

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Abstract

A design for a microwave assisted magnetic recording device is disclosed wherein a spin torque oscillator (STO) between a main pole and write shield has a spin polarization (SP) layer less than 30 Angstroms thick and perpendicular magnetic anisotropy (PMA) induced by an interface with one or two metal oxide layers. Back scattered spin polarized current from an oscillation layer is used to stabilize SP layer magnetization. One or both of the metal oxide layers may be replaced by a confining current pathway (CCP) structure. In one embodiment, the SP layer is omitted and spin polarized current is generated by a main pole/metal oxide interface. A direct current or pulsed current bias is applied across the STO. Rf current may also be injected into the STO to reduce critical current density. A write gap of 25 nm or less is achieved while maintaining good STO performance.

Claims17

Dependent claims

A microwave assisted magnetic recording (MAMR) structure that includes a write head, comprising:

(a) a main pole that generates a magnetic flux field which is directed through a pole tip at an air bearing surface (ABS) and into a magnetic medium to write one or more bits, the magnetic flux has a gap field component that is directed across a spin torque oscillator (STO) and into a write shield;
(b) the write shield with a side along the ABS that collects magnetic flux which has passed through the magnetic medium and written the one or more bits;
(c) an external current source that produces a direct current bias or pulsed current bias between the main pole and write shield, and across the STO;
and
(d) the STO that is formed along the ABS and generates a if field on the magnetic medium and thereby assists the writing to one or more bits, the STO comprises;
(1) a spin polarization (SP) layer which is selected from CoFeB, CoFe, CoFeNi, CoB, or FeB with perpendicular magnetic anisotropy (PMA) that spin polarizes the bias current in a direction perpendicular to a top surface of the SP layer and towards an oscillation layer (OL);
(2) the oscillation layer (OL) wherein the spin polarized bias current of a critical current density from the SP layer causes magnetization in the OL to oscillate with a sufficiently large angle and frequency to generate the if field on the magnetic medium to assist the writing to one or more bits;
(3) a non-magnetic spacer between the SP layer and OL, the non-magnetic spacer comprises one or more metal oxides;
(4) a seed layer formed between the main pole and the SP layer, the seed layer is a metal oxide layer consisting of AlOx, TaOx, or RuOx, a laminate of one or more of AlOx, TaOx, and RuOx, or a laminate of MgO with one or more of AlOx, TaOx, and RuOx;
and
(5) a capping layer formed between the OL and the write shield wherein the seed layer and the non-magnetic spacer induce the PMA in the SP layer.

8 more elements

A method to form a microwave assisted magnetic recording (MAMR) write head, comprising:

(a) providing a main pole that generates magnetic flux which is directed through a main pole tip at an air bearing surface (ABS) and into a magnetic medium comprised of a plurality of bits, the magnetic flux has a gap field component that is directed across a spin torque oscillator (STO) and into a write shield;
(b) forming the STO on the main pole, the STO comprises:
(1) a seed layer that contacts a surface of the main pole that faces a down-track direction, the seed layer is a metal oxide layer consisting of AlOx, TaOx, or RuOx, a laminate of one or more of AlOx, TaOx, and RuOx, or a laminate of MgO with one or more of AlOx, TaOx, and RuOx;
(2) a spin polarization (SP) layer which is selected from CoFeB, CoFe, CoFeNi, CoB, or FeB having a bottom surface contacting the seed layer, the SP layer has perpendicular magnetic anisotropy (PMA) and spin polarizes a bias current from an external current source in a direction perpendicular to a top surface of the SP layer and towards an oscillation layer (OL);
(3) a non-magnetic spacer that contacts the top surface of the SP layer and a bottom surface of the OL, the non-magnetic spacer comprises one or more metal oxides;
(4) the oscillation layer (OL) wherein the spin polarized current from the SP layer has a critical current density that causes magnetization in the OL to oscillate with a sufficiently large angle and frequency to generate a rf field on the magnetic medium to assist the writing to one or more bits;
and
(5) a capping layer formed on a top surface of the OL, and wherein the seed layer and the non-magnetic spacer induce the PMA in the SP layer;
(d) forming the write shield on the capping layer;
and
(e) connecting the external current source by a lead to the main pole and with a lead to the write shield.

8 more elements

Dependencies are inferred from the claim text.

Facts

Application: 14/468,399Filed 26 Aug 2014
Granted: 5 Jan 2016
Term ends: Not estimatedThe source records don’t support an estimate.

Classification8 codes

G11B 5/315
Magnetic layers: shield layers on both sides of the main pole, e.g. in perpendicular magnetic heads
G11B 5/1278
Structure or manufacture of heads, e.g. inductive: specially adapted for magnetisations perpendicular to the surface of the record carrier
G11B 5/147
Structure or manufacture of heads, e.g. inductive: with cores being composed of metal sheets, i.e. laminated cores with cores composed of isolated…
G11B 5/314
Including layers not usually being a part of the electromagnetic transducer structure and providing additional features, e.g. for improving heat…:…