Thermally-assisted magnetic recording head including plasmon generator

Abstract

A plasmon generator has an outer surface including a plasmon exciting part that faces an evanescent light generating surface of a waveguide. The outer surface further includes first and second inclined surfaces that increase in distance from each other with increasing distance from the plasmon exciting part, and a front end face. The front end face has first and second portions that are connected to each other into a V-shape. The first portion includes a first side lying at an end of the first inclined surface. The second portion includes a second side lying at an end of the second inclined surface. An angle formed between a lower part of the first side and a lower part of the second side is smaller than that formed between an upper part of the first side and an upper part of the second side.

Description

BACKGROUND OF THE INVENTION[0001]1. Field of the Invention[0002]The present invention relates to a thermally-assisted magnetic recording head including a plasmon generator for use in thermally-assisted magnetic recording where a magnetic recording medium is irradiated with near-field light to lower the coercivity of the magnetic recording medium for data writing.[0003]2. Description of the Related Art[0004]Recently, magnetic recording devices such as magnetic disk drives have been improved in recording density, and thin-film magnetic heads and magnetic recording media of improved performance have been demanded accordingly. Among the thin-film magnetic heads, a composite thin-film magnetic head has been used widely. The composite thin-film magnetic head has such a structure that a read head including a magnetoresistive element (hereinafter, also referred to as MR element) intended for reading and a write head including an induction-type electromagnetic transducer intended for writing...

AI Technical Summary

Benefits of technology

[0017]It is an object of the present invention to provide a thermally-assisted magnetic recording head that allows efficient use of the light propagated through the core of the waveguide, allows generation of near-field light having a small spot diameter from the plasmon generator, and allows the position of occurrence of the write magnetic field and the position of the occurrence of the near-field light to be close to each other, and to provide a method of manufacturing the thermally-assisted magnetic recording head, and a head gimbal assembly and a magnetic recording device that each include the thermally-assisted magnetic recording head.

[0031]According to the present invention, a surface plasmon is excited on the plasmon exciting part of the plasmon generator through coupling with the evanescent light generated from the evanescent light generating surface of the core of the waveguide. The near-field light generating part generates near-field light based on the surface plasmon. According to the present invention, it is thereby possible to transform the light propagated through the core into near-field light with high efficiency.

[0032]In the present invention, the outer surface of the plasmon generator includes the first and second inclined surfaces and the front end face. The front end face has the first and second portions connected to each other into a V-shape. The first portion includes the first side lying at the end of the first inclined surface. The second portion includes the second side lying at the end of the second inclined surface. Each of the first side and the second side includes the upper and lower parts continuous with each other. The angle formed between the lower part of the first side and the lower part of the second side is smaller than that formed between the upper part of the first side and the upper part of the second side. Consequently, according to the present invention, it is possible to match the wave number of the surface plasmons to be excited on the plasmon generator with the wave number of the evanescent light, and to reduce the spot diameter of the near-field light by making the angle between the lower part of the first side and the lower part of the second side smaller. The present invention thus makes it possible to use the light propagated through the core of the waveguide with high efficiency and to produce near-field light with a small spot diameter from the plasmon generator.

[0033]In the present invention, the end face of the magnetic pole located in the medium facing surface has the portion interposed between the first and second portions of the front end face. Consequently, according to the present invention, it is possible to locate the position of occurrence of the write magnetic field and the position of occurrence of the near-field light close to each other.

Problems solved by technology

However, making the magnetic fine particles smaller causes the problem that the thermal stability of magnetization of the magnetic fine particles decreases with decreasing volume of the magnetic fine particles.

However, increasing the anisotropic energy of the magnetic fine particles leads to an increase in coercivity of the magnetic recording medium, and this makes it difficult to perform data writing with existing magnetic heads.

However, the plasmon antenna which generates near-field light by direct irradiation with light is known to exhibit very low efficiency of transformation of the applied light into near-field light.

This causes an end of the read head located in the medium facing surface to get farther from the magnetic recording medium, thereby causing the problem that a servo signal cannot be read during write operations.

Making the inclination angle smaller, however, gives rise to the problem that the wave number of the surface plasmons to be excited on the plasmon generator does not match with the wave number of the evanescent light.

This decreases the surface plasmons to be excited on the edge part, thereby decreasing the use efficiency of the light propagated through the core.

When a thermally-assisted magnetic recording head employs such a configuration that the light propagated through the core is coupled with the plasmon generator in a surface plasmon mode through a buffer part, there arises the following problem if the position of occurrence of the write magnetic field and the position of occurrence of the near-field light are located close to each other.

The presence of such a magnetic pole near the core causes the problem that part of the light propagated through the core is absorbed by the magnetic pole and the use efficiency of the light propagated through the core thereby decreases.

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