Microwave assisted magnetic recording head having spin torque oscillator, and magnetic recording apparatus

摘要

A spin torque oscillator is provided which is adapted to high data transfer rates and which can perform assisted magnetic recording of sufficient magnitude. A spin torque oscillator is provided with a stacked spin injection layer and a high frequency magnetic field generation layer. The stacked spin injection layer has a stacked structure in which a first magnetic layer, a coupling layer, and a second magnetic layer are stacked in the order mentioned from a far side as viewed from the high frequency magnetic field generation layer. Magnetization of the first magnetic layer and magnetization of the second magnetic layer are coupled antiparallel to each other. A polarity of the magnetization of the second magnetic layer is reversed temporally earlier than a magnetic field polarity reversal of a leakage magnetic field from the main magnetic pole.

主权项

1. A magnetic recording head comprising:
a main magnetic pole configured to generate a recording field; and a spin torque oscillator, wherein: the spin torque oscillator includes a stacked spin injection layer and a high frequency magnetic field generation layer; the stacked spin injection layer has a stacked structure including a first magnetic layer, a coupling layer, and a second magnetic layer that are stacked in the order mentioned from a far side as viewed from the high frequency magnetic field generation layer; the spin torque oscillator is configured so that magnetization of the first magnetic layer and magnetization of the second magnetic layer are coupled antiparallel to each other; and the following relationship is satisfied:
Bs1×t1≧Bs2×t2 and Hkeff1>Hkeff2  where Bs1×t1 is the product of a saturation magnetic flux density and a film thickness of the first magnetic layer, Bs2×t2 is the product of a saturation magnetic flux density and a film thickness of the second magnetic layer, Hkeff1 is an effective magnetic anisotropy field of the first magnetic layer, and Hkeff2 is an effective magnetic anisotropy field of the second magnetic layer, where the effective magnetic anisotropy field is defined as the sum of a crystalline magnetic anisotropy magnetic field and a shape magnetic anisotropy magnetic field.