Fujitsu Corporation

Showa Denko K.k.

Akita University

Iwao Okamoto

E Noel Abarra

Kenji Sato

Yuki Yoshida

Isatake Kaitsu

Chiaki Okuyama

Yoshifumi Mizoshita

Masayoshi Shinohara

Hisashi Umeda

Hideyuki Akimoto

Hisateru Sato

B Ramamurthy Acharya

Antony Ajan

Takashi Hasegawa

Minoru Takahashi

Kazunori Yamanaka

Kiyoshi Yamaguchi

Yasuo Bamba

Yasuji Ikeda

Wataru Yamagishi

Seigo Igaki

Hitoshi Saito

Takahisa Ueno

Tohru Horie

Shunji Ishio

Haruhiro Komura

Naoya Yamamoto

A magnetic recording medium for use in digital magnetic recording, which comprises a nonmagnetic substrate having deposited thereon a magnetic layer, wherein with respect to the in-plane direction, the magnetic recording layer comprises a plurality of ferromagnetic regions separated from each other by an antiferromagnetic region. A production method of the magnetic recording medium and a magnetic disc apparatus are also disclosed.

Magnetic recording medium, production method thereof and magnetic disc apparatus

A magnetic recording medium is provided with a first magnetic layer, a nonmagnetic coupling layer provided on the first magnetic layer, and a second magnetic layer provided on the nonmagnetic coupling layer. The first and second magnetic layers are exchange-coupled, and have magnetization directions which are mutually parallel in a state where no external magnetic field is applied thereto, and the first magnetic layer switches the magnetization direction thereof before the second magnetic layer in response to a recording magnetic field which switches the magnetization directions of the first and second magnetic layers.

Magnetic recording medium, magnetic storage apparatus and recording method

A magnetic recording medium is provided with an exchange layer structure, and a magnetic layer provided on the exchange layer structure. The exchange layer structure includes a ferromagnetic layer and a nonmagnetic coupling layer provided on the ferromagnetic layer, where the ferromagnetic layer and the magnetic layer are exchange-coupled and having mutually antiparallel magnetizations. The ferromagnetic layer and the magnetic layer satisfy a relationship Hc'&#x2267;Hc&#x2032;, where Hc&#x2032; denotes a dynamic coercivity of the ferromagnetic layer and Hc&#x2032; denotes a dynamic coercivity of the magnetic layer.

Magnetic recording medium having at least two coupled magnetic layers, magnetic storage apparatus and recording method

A magnetic recording medium including a textured surface that is textured in a predetermined direction. The textured surface preferably has a distance &#x3bb; between two mutually adjacent texturing lines satisfying a relationship 5&#x3c;&#x3bb;&#x3c;30 nm, and an angle &#x3c6; between the textured surface and an oblique texture plane satisfying a relationship 0.5&#x3c;&#x3c6;&#x3c;7 degrees. There is also a Cr-based underlayer provided on the textured surface that has a preferred growth so that a number of grains having Cr&#x3c;110&#x3e; in a vicinity of 0 degrees or 90 degrees with respect to the predetermined direction is two times or greater than a number of grains having Cr&#x3c;110&#x3e; in a vicinity of 45 degrees with respect to the predetermined direction. Additionally, there is also a Co-based magnetic layer provided on the underlayer that has Co(1120) preferred growth along the predetermined direction.

Magnetic recording medium with CR &#x3c;110&#x3e; preferred growth along a predetermined direction, method of producing the same and magnetic storage apparatus

After a measurement apparatus records a magnetization state of a reference pattern on at least one specific track of a recording medium, it generates a leakage magnetic field of a demagnetization pattern and demagnetizes the magnetization state of the reference pattern using the leakage magnetic field. Then, the measurement apparatus calculates a difference between the read output of a reference pattern before demagnetization and the read output of a reference pattern after demagnetization on the specific track and obtains a leakage magnetic field of a recording head from the obtained difference.

Apparatus and method of measuring write magnetic field of recording head

A magnetic recording medium includes a textured surface which is textured in a predetermined direction, a Cr-based underlayer provided on the textured surface and having Cr&#x3c;110&#x3e; preferred growth along the predetermined direction so that over approximately 50% of Cr&#x3c;110&#x3e; are oriented along the predetermined direction, and a Co-based magnetic layer provided on the underlayer and having Co(1120) preferred growth along the predetermined direction.

Magnetic recording medium with Cr&#x3c;110&#x3e; preferred growth along a predetermined direction, method of producing the same and magnetic storage apparatus

A magnetic recording medium has first, second and third magnetic layers having magnetization directions which are alternately antiparallel in a state where no external magnetic field is applied on the magnetic recording medium, with a first nonmagnetic layer interposed between the first and second magnetic layers and a second nonmagnetic layer interposed between the second and third magnetic layers. A relationship Ms&#xd7;t&#x3c;(Ms&#xd7;t+Ms&#xd7;t) stands, where Ms, Msand Ms, and t, tand trespectively denote saturation magnetizations and thicknesses of the first, second and third magnetic layers.

Antiferromagnetically coupled magnetic recording medium possessing three coupled magnetic layers and magnetic storage apparatus

A magnetic recording medium is constructed to include a substrate, a magnetic layer made of a Co or Co-based alloy, and an underlayer disposed between the substrate and the magnetic layer. The underlayer is made of an ordered intermetallic material of FCC L1 or FCT L1 crystalline structure, so that c-axis of the magnetic layer is aligned in a predetermined direction.

Magnetic recording medium and magnetic storage apparatus

A magnetic recording medium is constructed to include at least one exchange layer structure, and a magnetic layer formed on the exchange layer structure, where the exchange layer structure comprises a ferromagnetic layer, and a non-magnetic coupling layer provided on the ferromagnetic layer and under the magnetic layer. The ferromagnetic layer and the magnetic layer have antiparallel magnetizations. The non-magnetic coupling layer is made of a Ru-M3 alloy, where M3 is an added element or alloy, and a lattice mismatch between the non-magnetic coupling layer and the magnetic layer and the ferromagnetic layer respectively disposed above and below the non-magnetic coupling layer is adjusted to approximately 6% or less by addition of M3.

The present invention relates to a magnetic recording medium for use in an external memory device of an information processing apparatus etc., and an object thereof is to reduce noise, achieve high coercive force, and use the substance as a magnetic recording medium for detecting signals in a magnetoresistance head. In the magnetic recording medium comprising the magnetic recording layer including ferromagnetic grains and a nonmagnetic substance , the improvement in structure comprises that the ferromagnetic grains are formed to have respectively an average grain diameter of 50 nm or less and not to be overlapped in the film thickness direction and to be isolated in the direction along a layer surface, and that a product of residual magnetization and a film thickness of the magnetic recording layer is less than or equal to 150 Gauss&bull;&mgr;m.

Magnetic recording medium

A magnetic recording medium is provided with at least one exchange layer structure, and a magnetic layer formed on the exchange layer structure. The exchange layer structure includes a ferromagnetic layer and a non-magnetic coupling layer provided on the ferromagnetic layer and under the magnetic layer.

Magnetic recording medium, magnetic storage apparatus, recording method and method of producing magnetic recording medium

A magnetic recording medium and a magnetic disk device using the same. The magnetic recording medium comprising a nonmagnetic substrate having applied thereon, through two or more chromium-based underlayers, a magnetic recording layer having a circumferential direction of easy magnetization and containing cobalt as a principal component thereof, and also containing chromium and platinum in combination with tantalum or tantalum and niobium. Using the magnetic recording medium, a reproducing output and S/N ratio can be increased without causing an increase in noise.

Magnetic recording medium possessing a ratio of Hc(perpendicular) to Hc(horizontal) that is not more than 0.22 and magnetic recording disk device

A magnetic recording medium is constructed to include at least one exchange layer structure and a magnetic layer provided on the exchange layer structure. The exchange layer structure includes a ferromagnetic layer and a non-magnetic coupling layer provided on the ferromagnetic layer. At least one of the ferromagnetic layer and the magnetic layer has a granular layer structure in which ferromagnetic crystal grains are uniformly distributed within a non-magnetic base material.

A magnetic recording medium includes a substrate, a nonmagnetic seed layer provided on the substrate, and a magnetic layer provided on the nonmagnetic seed layer via one or a plurality of layers. The nonmagnetic seed layer is made of NiAl having an oxygen concentration of approximately 1500 to 4000 ppm.

Growing community of inventors

Kawasaki, Japan

Iwao Okamoto