Tdk Corporation

Masahide Kohno

Tsunehiko Ikarashi

Hideki Sasaki

Kazumasa Fukuda

Kunihiro Ueda

Hiroshi Kiyono

Katsumichi Tagami

Shunji Saruki

Osamu Inoue

Tetsuya Kuwashima

Kenji Inage

Yasufumi Takasugi

Shinji Miyazaki

Kazuhiro Kuroda

Hiromichi Kanazawa

Katsuaki Yanagiuchi

Yasushi Ishikawa

A TMR effect element with sufficiently reduced element resistance and restricted popping noise is provided, which comprises a tunnel barrier layer formed primarily of a metal oxide including many electric charge sites. The electric charge sites density n and the mobility &#x3bc; of electrons trapped due to the electric charge sites satisfy a relationship expressed by: 0&#x3c;(n&#x2212;n)&#xb7;(&#x3bc;&#x2212;&#x3bc;)&#xb7;(n&#x3bc;)&#x3c;0.2, where nand nare densities of tunnel electrons when an element resistance is a minimum and maximum respectively during reading signals and &#x3bc;is the mobility of electrons when not trapped.

Tunnel magnetoresistive effect element with limited electric popping output voltage

A magnetic recording medium includes a non-magnetic supporting substrate, and a magnetic layer on one surface thereof and a back coat layer on the other surface thereof, said back coat layer having a non-magnetic powder dispersed in a binder. The back coat layer contains carbon black and an inorganic powder as said non-magnetic powder. The carbon black contains a carbon black species having an average primary particle diameter of 40 to 70 nm, and the inorganic powder has an average primary particle diameter of 40 to 150 nm and a Mohs hardness of at least 3, with a weight ratio between said carbon black and said inorganic powder being 100:0.5 to 100:10. The binder comprises a phenoxy resin, a thermoplastic polyurethane resin having an amino group in a molecule thereof, and a polyisocyanate compound.

Magnetic recording medium

A magnetic recording (vapor deposition) film medium having improved friction characteristics, running durability, and still characteristics are provided. The magnetic recording thin film medium comprises a non-magnetic support having on at least one surface thereof a magnetic layer, a protective layer formed on the magnetic layer, and a lubricant layer formed on the protective layer, wherein the magnetic recording medium is obtained by that after forming the magnetic layer on the surface of the non-magnetic support conveyed along the surface of a cooling roll, a carbon-containing plasma polymerized film is formed on the magnetic layer as the protective layer, while conveying the non-magnetic support having the magnetic layer along the surface of a cooling roll, and after surface-treating the carbon-containing plasma polymerized film on the same cooling roll as the protective layer-forming roll or on a different cooling roll from the protective layer-forming roll without applying a bias voltage to the surface-treatment roll, whereby a double bond component of carbon and oxygen is incorporated in the surface of the carbon-containing plasma polymerized film at a ratio of from 1.4 to 7.5 atomic % to the whole carbon amount of the surface of the carbon-containing plasma polymerized film, and the lubricant layer made up of an ester of a fluorinated alcohol and a fatty acid is then formed on the carbon-containing plasma polymerized film.

In a magnetic recording medium comprising on a non-magnetic substrate a magnetic layer obtained by dispersing ferromagnetic powder in an electron beam-curable resin followed by electron beam curing or a backcoat layer obtained by curing an electron beam-curable resin with electron beams, a combination of an electron beam-curable vinyl chloride resin having a sulfur-containing polar group and an electron beam-curable urethane resin having a phosphorus-containing polar group is used as the electron beam-curable resin. This results in improvements in dispersibility, surface smoothness, and electromagnetic characteristics, as well as a lowering of error rate in high density digital recording. Storage property is good.

Growing community of inventors

Nagano, Japan

Masahide Kohno