Magnetic powder for magnetic recording medium

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United States of America Patent

PATENT NO 9741479
SERIAL NO

14529544

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Abstract

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Provided is magnetic powder capable of enhancing simultaneously both magnetic characteristics including SNP and durability of a magnetic recording medium. The hexagonal ferrite magnetic powder for a magnetic recording medium has a Ba/Fe molar ratio of 8.0% or more, a Bi/Fe molar ratio of 2.5% or more and an Al/Fe molar ratio of from 3.0 to 6.0%. The magnetic powder preferably has an activation volume Vact of from 1,400 to 1,800 nm3. The magnetic powder particularly preferably has a coercive force Hc of from 159 to 279 kA/m (which is approximately from 2,000 to 3,500 Oe) and a coercivity distribution SFD of from 0.3 to 1.0. The magnetic powder may contain, as an element that substitutes an Fe site of the hexagonal ferrite, at least one kind selected from divalent transition metals M1 and tetravalent transition metals M2.

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Patent Owner(s)

Patent OwnerAddress
FUJIFILM CORPORATION26-30 NISHIAZABU 2-CHOME MINATO-KU TOKYO 106-8620
DOWA ELECTRONICS MATERIALS CO LTD4-14-1 SOTOKANDA CHIYODA-KU TOKYO 1010021 ?1010021

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Inventor(s)

Inventor Name Address # of filed Patents Total Citations
Abe, Daisuke Tokyo, JP 146 1998
Kasada, Norihito Kanagawa, JP 284 15964
Masada, Kenji Tokyo, JP 18 170
Nagashima, Futoshi Tokyo, JP 2 110
Omoto, Hirohisa Tokyo, JP 8 113
Tada, Toshio Kanagawa, JP 50 3320

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