Kabushiki Kaisha Toshiba

Akihiko Tsutai

Shinya Sakurada

Masashi Sahashi

Takahiro Hirai

Akiko Saito

Koichiro Inomata

Tetsuhiko Mizoguchi

Isao Sakai

Hitoshi Iwasaki

Hiroaki Yoda

Kazuhiro Saito

Yuichi Ohsawa

Yuzo Kamiguchi

Tadahiko Kobayashi

Takao Sawa

Wu Mei

Masami Okamura

Yoichi Tokai

Michihiko Inaba

Tomohisa Arai

Keisuke Hashimoto

Hiromi Niu

Hideo Nagai

Toshiya Sakamoto

Tsutomu Yamashita

Yoshitaka Yanagita

Masahi Sahashi

Yukiko Nishiyama

Permanent magnet

A magnetic yoke having a magnetic gap provided in the side of the surface facing the medium is disposed on the surface of a substrate. An MR film is disposed on the surface of the magnetic yoke substantially parallel to the substrate with a predetermined separation from the surface S facing the medium. At least both end portions of the MR film are magnetically coupled to the magnetic yoke. A pair of leads for supplying sensing current to the MR film have magnetic lead portions formed from the same magnetic layers as the magnetic yoke. The magnetic lead portions curb deterioration of MR head properties and yield reduction during formation of the leads. Furthermore, a bias magnetic field is applied to the magnetic yoke and the MR film at least during operation of the head. This bias magnetic field is for instance provided by a magnetic field induced by the electric current. Alternatively, a magnetic field induced by the electric current is applied while heat-processing the magnetic yoke. Magnetic anisotropy is induced to the magnetic yoke in a direction differing according to the position. This magnetic anisotropy curbs Barkhausen noise caused by the magnetic yoke.

Yoke type magnetoresistance head and manufacturing method of the same

There is provided a magnetic material having a TbCu.sub.7 phase as a principal phase and excellent in residual magnetic flux density. This magnetic material is formed of a composition represented by a general formula:

Magnetic material and bonded magnet

Disclosed is a magnetic material which exhibits an improved saturation magnetic flux density and an improved magnetic anisotropy and, thus, is adapted for use as a raw material of a permanent magnet or a bond magnet of a high performance. The magnetic material is represented by a general formula

Magnetic material

The regenerating material according to the present invention comprises two alloy phases which differ in a content of rare earth elements. Of these alloy phases, a dominant phase in the regenerating material is defined as a main phase, and the other phase is defined as a sub-phase. A plurality of particles, each of which consists of a granular main phase and a sub-phase present on the surface of the main phase, gathers to form an aggregate. Otherwise, a sub-phase present in a main phase in the form of fiber. The refrigerator according to the present invention comprises a regenerator charged with above-mentioned regenerating material, a coolant gas and an expansion means for expanding the coolant gas.

Regenerating material and refrigerator using the same

A permanent magnet is composed of a magnetic material which is represented by a general formula R1.sub.x R2.sub.y A.sub.z Co.sub.u Fe.sub.100-x-y-z-u (where R1 is at least one element selected from rare earth elements, R2 is at least one element selected from the group consisting of Sc, Zr and Hf, A is at least one element selected from the group of C, N and P, and x,y,z and u are atomic percent defined as 2.ltoreq.x, 4.ltoreq.x+y.ltoreq.20, 0.ltoreq.z.ltoreq.20, 0.ltoreq.u.ltoreq.70), wherein the material includes a principal phase of TbCu.sub.7 structure and .alpha.-Fe, a peak width at half height of the main peak of X-ray diffraction of the principal phase obtained by using Cu-K.alpha. X-rays with the resolution of 0.02.degree. or less is about 0.8.degree. or less, and a ratio of peak intensity between the principal phase and .alpha.-Fe satisfies a relation that the value of I.sub.Fe /(I.sub.p +I.sub.Fe) is about 0.4 or less where I.sub.p is the peak intensity of main peak of X-ray diffraction of the principal phase obtained by using Cu-K.alpha. X-rays and I.sub.Fe is that of .alpha.-Fe.

A magnetic material with an improved maximum energy product useful for high performance permanent magnet, bond magnet and other applications is disclosed. The magnetic material is expressed in a general formula R1.sub.x R2.sub.y M.sub.100-x-y where R1 is at least one element selected from the rare earth elements, R2 is at least one element selected from elements having an atomic radius in a range of 0.156 to 0.174 nm, M is at least one element selected from Fe and Co and x and y are atomic percent individually defined as x.gtoreq.2, y.gtoreq.0.01 and 4.ltoreq.x+y.ltoreq.20, and M occupying 90 atomic percent or more in the principal phase of the compound.

Disclosed is a magnetic material which suppresses formation of impurity phase of Fe, Co or Fe-Co alloy, possesses a stable ThMn.sub.12 crystal structure as the principal phase, and is excellent in magnetic properties and lower in cost. Such magnetic material is expressed in a general formula:

In a method for producing a resin-bonded rare earth-iron-boron magnet, a powder is subjected to a heat-treatment below its melting point. The powder can be either: (1) a mixture of both: (a) a powder of a rare earth-iron-boron magnetic alloy comprising about 8 to about 30 atomic percent of R, which stands for at least one selected from the group of Y (yttrium) and rare earth elements, about 2 to about 28 atomic precent of B(boron), and at least 50 atomic percent of Fe(iron) and (b) at least one of the group consisting of R, R-oxides, which are oxides of R, and R-compound, which are the compounds consisting essentially of more than 30 atomic percent of R and the balance substantially of at least one of Fe and Co; or (2) a rare earth-iron-boron magnetic alloy comprising about 8 to about 30 atomic percent of R, about 2 to about 28 atomic percent of B, about 0.1 to about 13 atomic percent of Ga, and at least 50 atomic percent of Fe. The resultant heat-treatment powder is then bonded with a resin. The present invention also includes a magnet such as might be made by such a method.

Resin-bonded rare earth-iron-boron magnet

A permanent magnet essentially consists of 10 to 40% by weight of R, 0.1 to 8% by weight of boron, 13% by weight or less of gallium and iron, where R is at least one component selected from the group consisting of yttrium and the rare-earth elements. The magnet having this composition has a high coercive force iHC and a high residual magnetic flux density and therefore has a high maximum energy product.

Growing community of inventors

Kawasaki, Japan

Akihiko Tsutai