公开(公告)号：US20210012805A1

公开(公告)日：2021-01-14

申请号：US16969876

申请日：2019-02-18

Applicant: Sony Corporation

Inventor： Masaru TERAKAWA ,  Minoru YAMAGA ,  Takanobu IWAMA ,  Jun TAKAHASHI

IPC: G11B20/12 ,  G11B5/733 ,  G11B5/706 ,  G11B5/008

Abstract: [Object] Provided is a technology that is capable of further improving a recording density of data.
[Solving Means] A magnetic recording medium according to the present technology is a magnetic recording medium in a shape of a tape that is long in a longitudinal direction and is short in a width direction, the medium including: a base material; a magnetic layer; and a non-magnetic layer that is provided between the base material and the magnetic layer, and contains one or more types of non-magnetic inorganic particles, in which the magnetic layer includes a data band long in the longitudinal direction in which a data signal is to be written, and a servo band long in the longitudinal direction in which a servo signal is written, and in the magnetic layer, a degree of vertical orientation is greater than or equal to 65%, a half width of a solitary waveform in a reproduction waveform of the servo signal is less than or equal to 195 nm, and a thickness of the magnetic layer is less than or equal to 90 nm, and the non-magnetic layer contains at least Fe-based non-magnetic particles as the non-magnetic inorganic particles, and in the non-magnetic layer, an average particle volume of the Fe-based non-magnetic particles is less than or equal to 2.0×10−5 μm3, and a thickness of the non-magnetic layer is less than or equal to 1.1 μm.

公开(公告)号：US20200312364A1

公开(公告)日：2020-10-01

申请号：US16455188

申请日：2019-06-27

Applicant: SONY CORPORATION

Inventor： Masaru TERAKAWA ,  Minoru YAMAGA

IPC: G11B5/73 ,  G11B5/733 ,  G11B5/65 ,  G11B5/667

Abstract: A magnetic recording medium includes a layer structure including a magnetic layer, a non-magnetic layer, and a base layer in this order, in which an average thickness tT is tT≤5.5 μm, a dimensional variation Δw in a width direction to tension change in a longitudinal direction is 660 ppm/N≤Δw, and an average thickness tn of the non-magnetic layer is tn≤1.0 μm.

公开(公告)号：US20190013043A1

公开(公告)日：2019-01-10

申请号：US16070140

申请日：2016-12-14

Applicant: Sony Corporation

Inventor： Eiji NAKASHIO ,  Masaru TERAKAWA ,  Yoichi KANEMAKI ,  Tomoe SATO ,  Katsunori MAESHIMA ,  Nobuyuki SASAKI

IPC: G11B5/65

Abstract: The magnetic recording medium includes a long substrate body, and a magnetic layer including a powder of cubic crystal ferrite magnetic particles. The sum of a squareness ratio in the longitudinal direction and a squareness ratio in the vertical direction is 1.2 or more, and the difference of the squareness ratio in the longitudinal direction and the squareness ratio in the vertical direction is 0.15 or more.

公开(公告)号：US20220230660A1

公开(公告)日：2022-07-21

申请号：US17715365

申请日：2022-04-07

Applicant: SONY CORPORATION

Inventor： Masaru TERAKAWA ,  Minoru YAMAGA

IPC: G11B5/62 ,  G11B5/733 ,  G11B5/706 ,  G11B5/735 ,  G11B5/596 ,  G11B5/68

Abstract: A magnetic recording medium is provided and includes a layer structure including a magnetic layer, a non-magnetic layer, and a base layer in order, in which an average thickness tT of the magnetic recording medium is 4.0 μm≤tT≤5.3 μm, a dimensional variation Δw in a width direction of the magnetic recording medium to tension change in a longitudinal direction of the magnetic recording medium is 680 ppm/N≤Δw≤2000 ppm/N , and an average thickness tn of the non-magnetic layer is tn≤1.0 μm.

公开(公告)号：US20210027807A1

公开(公告)日：2021-01-28

申请号：US17043452

申请日：2019-03-27

Applicant: SONY CORPORATION

Inventor： Natsuki TOYOSAWA ,  Norikatsu FUJISAWA ,  Yuta AKIMOTO ,  Satoru ABE ,  Masaru TERAKAWA ,  Katsunori MAESHIMA ,  Atsushi MURAMATU ,  Masashi NAKATANI

IPC: G11B5/842 ,  H01F1/11 ,  G11B5/706 ,  C01G49/04 ,  C01G49/08 ,  C09C1/24

Abstract: [Solving Means] A method of producing a magnetic powder includes: coating a surface of each of silica-coated precursor particles with at least one type of coating agent of a metal chloride or a sulfate; and firing the precursor particles coated with the coating agent.

公开(公告)号：US20200118589A1

公开(公告)日：2020-04-16

申请号：US16617960

申请日：2019-04-01

Applicant: Sony Corporation

Inventor： Masaru TERAKAWA ,  Minoru YAMAGA ,  Katsunori MAESHIMA

IPC: G11B5/78 ,  G11B5/584 ,  G11B5/008

Abstract: A tape-shaped magnetic recording medium includes a substrate; and a magnetic layer that is provided on the substrate and contains a magnetic powder. An average thickness of the magnetic layer is not more than 90 nm, an average aspect ratio of the magnetic powder is not less than 1.0 and not more than 3.0, the coercive force Hc1 in a vertical direction is not more than 3000 Oe, the coercive force Hc1 in the vertical direction and a coercive force Hc2 in a longitudinal direction satisfy a relationship of Hc2/Hc1≤0.8, and a value of σ1.5-σ0.5 is not more than 0.6 N in a tensile test of the magnetic recording medium in the longitudinal direction, where σ0.5 is a load at an elongation rate of 0.5% in the magnetic recording medium and σ1.5 is a load at an elongation rate of 1.5% in the magnetic recording medium.

公开(公告)号：US20180114541A1

公开(公告)日：2018-04-26

申请号：US15565050

申请日：2016-03-08

Applicant: Sony Corporation

Inventor： Eiji NAKASHIO ,  Futoshi SASAKI ,  Yuuichi MASUZAWA ,  Masaru TERAKAWA ,  Minoru YAMAGA ,  Yoichi KANEMAKI ,  Kazuya HASHIMOTO ,  Tomoe SATO ,  Nobuyuki SASAKI

IPC: G11B5/733 ,  G11B5/73

CPC classification number: G11B5/733 ,  G11B5/70 ,  G11B5/731

Abstract: Provided is a magnetic recording medium including: a support body; a base layer containing carbon particle powder and metal-containing particle powder; and a recording layer. In a recording surface, a maximum indentation depth h is 85≤h≤140, and a ratio d of a permanent strain to an elastic recovery (permanent strain/elastic recovery) is 0.95≤d≤1.25.

公开(公告)号：US20210350827A1

公开(公告)日：2021-11-11

申请号：US17272159

申请日：2019-09-05

Applicant: Sony Corporation

Inventor： Masaru TERAKAWA ,  Minoru YAMAGA

IPC: G11B5/706

Abstract: A magnetic recording medium used on a record/playback device with a minimum recording wavelength or 50 nm or shorter, the magnetic recording medium including a magnetic layer that contains a spinel-type ferrite magnetic powder, the magnetic layer having an average thickness of 85 nm or smaller, and the magnetic layer having a saturation flux density of 1600 Gauss or larger and 2000 Gauss or smaller.

公开(公告)号：US20210287714A1

公开(公告)日：2021-09-16

申请号：US16330010

申请日：2017-09-27

Applicant: SONY CORPORATION

Inventor： Atsushi MURAMATSU ,  Masafumi NAKAYA ,  Masaru TERAKAWA ,  Satoru ABE ,  Natsuki TOYOSAWA ,  Katsunori MAESHIMA

IPC: G11B5/714 ,  H01F1/11 ,  G11B5/65 ,  H01F1/06

Abstract: A method of producing a magnetic powder includes: performing heat treatment on first particles that contain triiron tetraoxide to prepare second particles that contain ε-iron oxide.

公开(公告)号：US20200372932A1

公开(公告)日：2020-11-26

申请号：US16992908

申请日：2020-08-13

Applicant: Sony Corporation

Inventor： Masaru TERAKAWA ,  Minoru YAMAGA ,  Katsunori MAESHIMA

IPC: G11B5/78 ,  G11B5/584 ,  G11B5/008

Abstract: A tape-shaped magnetic recording medium includes a substrate; and a magnetic layer that is provided on the substrate and contains a magnetic powder. An average thickness of the magnetic layer is not more than 90 nm, an average aspect ratio of the magnetic powder is not less than 1.0 and not more than 3.0, the coercive force Hc1 in a vertical direction is not more than 3000 Oe, the coercive force Hc1 in the vertical direction and a coercive force Hc2 in a longitudinal direction satisfy a relationship of Hc2/Hc1≤0.8, and a value of σ1.5−σ0.5 is not more than 0.6 N in a tensile test of the magnetic recording medium in the longitudinal direction, where σ0.5 is a load at an elongation rate of 0.5% in the magnetic recording medium and σ1.5 is a load at an elongation rate of 1.5% in the magnetic recording medium.