Tdk Corporation

Hokkaido University

Yuki Nagamine

Yoshinori Fujikawa

Kumiko Yamazaki

Takeshi Shibahara

Eiji Kato

Chikara Ishizaka

Katsuo Sato

Junichi Yamazaki

Wakako Okawa

Masashi Miwa

Masashi Ito

Yuji Umeda

Hiroshi Chihara

Ryuji Hashimoto

Tetsuya Hidaka

Yoshitomo Tanaka

Eiichiro Fukuchi

Yuji Masubuchi

Shinichi Kikkawa

An R-T-B based permanent magnet, excellent in magnetic properties relatively reducing amount of heavy rare earth element used, wherein R represents rare earth element, T iron group element and B boron, includes main phase grains including RTB crystal phase and grain boundaries between main phase grains. Grain boundaries include R&#x2014;O&#x2014;C&#x2014;N concentrated parts where concentrations of R, O, C and N are all higher than in main phase grains. O/R(S)&#x3e;O/R(C) wherein O/R(S) represents O/R ratio (atomic ratio) in R&#x2014;O&#x2014;C&#x2014;N concentrated parts in a surface of an R-T-B based permanent magnet and O/R(C) represents O/R ratio (atomic ratio) in R&#x2014;O&#x2014;C&#x2014;N concentrated parts in a center of an R-T-B based permanent magnet. A heavy rare earth element RH is in a surface of an R-T-B based permanent magnet as R. R&#x2014;O&#x2014;C&#x2014;N concentrated parts in a surface of an R-T-B based permanent magnet have RH/R ratio (atomic ratio) of 0.2 or less.

R-T-B based permanent magnet

To provide a rare earth permanent magnet having as a main phase a compound with a NdFecrystalline structure having strong coercive force. A rare earth permanent magnet having as a main phase a compound with a NdFecrystalline structure, wherein when the composition ratio of the rare earth permanent magnet is expressed as RTC, where R is one or more rare earth elements requiring Sm, and T is one or more transition metal elements requiring Fe or Fe and Co, a and b satisfy 18&#x3c;a&#x3c;40 and 0.5&#x2264;b, and a phase where R and C are denser than the main phase is provided in the grain boundary phase of the rare earth permanent magnet.

Rare-earth permanent magnet

A permanent magnet includes R and T (R essentially includes Sm one or more of rare earth elements in addition to Sm, and T essentially includes Fe, or Fe and Co, one or more of transition metal elements in addition to Fe, or Fe and Co). A composition ratio of R in the permanent magnet is 20 at % or more and 40 at % or less. A remaining part is substantially only T, or only T and C. T amount is more than 1.5 times of R amount and less than 4.0 times of the R amount. Main phase grains included in the permanent magnet have an Nd5Fe17 type crystal structure. An average crystal grain size of the main phase grains of the permanent magnet is greater than 1 &#x3bc;m. A number ratio of main phase grains having a crystal grain size of less than 0.4 &#x3bc;m is less than 20%.

Permanent magnet and permanent magnet powder

An R-T-B based permanent magnet excellent in magnetic properties relatively reduces the amount of a heavy rare earth element used. An R-T-B based permanent magnet, wherein R represents a rare earth element, T an iron group element and B boron, includes main phase grains including an RTB crystal phase and grain boundaries formed between main phase grains. Grain boundaries include R&#x2014;O&#x2014;C&#x2014;N concentrated parts where concentrations of R, O, C and N are all higher than those in main phase grains. C/R(S)&#x3e;C/R(C) is satisfied in which C/R(S) represents a C/R ratio (atomic ratio) in R&#x2014;O&#x2014;C&#x2014;N concentrated parts present in a surface of a R-T-B based permanent magnet and C/R(C) represents a C/R ratio (atomic ratio) in the R&#x2014;O&#x2014;C&#x2014;N concentrated parts present in the center of a R-T-B based permanent magnet, and a heavy rare earth element RH is included in the R-T-B based permanent magnet.

A metal oxynitride thin film having a perovskite structure, in which the metal oxynitride thin film has a composition represented by a compositional formula ABONwherein &#x3b1; is larger than zero and 0.300 or less, x+&#x3b1; is larger than 2.450, and y is 0.300 or more and 0.700 or less, an AO structure having a layered structure parallel to a plane perpendicular to a c-axis of the perovskite structure and having a composition represented by a general formula AO, and the AO structure is bonded with the perovskite structure and incorporated in the perovskite structure.

Metal oxynitride thin film, process for producing metal oxynitride thin film, and capacitor element

A polycrystalline dielectric thin film and a capacitor element have a large relative dielectric constant. The polycrystalline dielectric thin film has a perovskite oxynitride as a principal component. The perovskite oxynitride is represented by compositional formula ABON(a1+b1+o+n=5), and the a-axis length of the crystal lattice of the perovskite oxynitride is larger than a theoretical value.

Polycrystalline dielectric thin film and capacitor element

To provide a dielectric porcelain composition and an electronic component that demonstrate ferroelectricity. A dielectric porcelain composition that is characterized by having a perovskite-type oxynitride as a principal component and by including a polycrystalline body that demonstrates ferroelectricity.

Dielectric porcelain composition and electronic component

A polycrystalline dielectric thin film and capacitor element has a small dielectric loss tan &#x3b4;. The polycrystalline dielectric thin film, in which the main composition is a perovskite oxynitride. The perovskite oxynitride is expressed by the compositional formula AaBbOoNn (a+b+o+n=5), where a/b&#x3e;1 and n&#x2265;0.7.

A dielectric thin film has a main component including an oxynitride having excellent dielectric property, and a capacitance element includes the dielectric thin film. The dielectric thin film has a main component made of an oxynitride expressed by a compositional formula of ABON(a+b+o+n=5), wherein 'A' is one or more selected from Sr, Ba, Ca, La, Ce, Pr, Nd, and Na, 'B' is one or more selected from Ta, Nb, Ti, and W, and crystalline particles constituting the dielectric thin film are polycrystalline which are not oriented to a particular crystal plane orientation, and further the crystalline particles have columnar shape crystals.

Oxynitride thin film and capacitance element

The object of the present invention is to provide a dielectric thin film and a capacitance element having excellent dielectric property. A dielectric thin film comprising a main component comprised of an oxynitride expressed by a compositional formula of ABON(a+b+o+n=5), wherein said 'A' is one or more selected from the group consisting of Sr, Ba, Ca, La, Ce, Pr, Nd, and Na, said 'B' is one or more selected from the group consisting of Ta, Nb, Ti, and W, and crystalline particles constituting said dielectric thin film are polycrystalline which are not aligned to a particular crystal plane orientation, and a size of a crystallite of the crystalline particles included in the dielectric thin film is 100 nm or less.

A rare earth permanent magnet includes a main phase composed of a main phase particle and a grain boundary present among a plurality of the main phase particles. The grain boundary includes a region whose electric resistance is higher than that of the main phase.

Rare earth permanent magnet

The present invention provides a rare earth based magnet in which the demagnetization rate at a high temperature can be inhibited even if the amount of heavy rare earth element(s) such as Dy and Tb is evidently decreased compared to the past or no such heavy rare earth element is used. The rare earth based magnet of the present invention is a sintered magnet which comprises RTB crystal grains as the main phases and the crystal boundary phases among the RTB crystal grains. The microstructure of the sintered body is controlled by including crystal boundary phases containing at least R, T and M in the crystal boundary phases, wherein the relative atomic ratios of R, T and M are as follows, i.e., 25 to 35% for R, 60 to 70% for T and 2 to 10% for M.

Rare earth based magnet

The present invention provides a rare earth based magnet in which the demagnetization rate at a high temperature can be inhibited even if the amount of heavy rare earth element(s) such as Dy and Tb is evidently decreased compared to the past or no such heavy rare earth element is used. The rare earth based magnet of the present invention is a sintered magnet which comprises RTB crystal grains as the major phases and the crystal boundary phases among the RTB crystal grains. The microstructure of the sintered body is controlled by including crystal boundary phases containing at least R, T and M in the crystal boundary phases, wherein the relative atomic ratios of R, T and M are as follows, i.e., 60 to 80% for R, 15 to 35% for T and 1 to 20% for M.

The present invention provides a rare earth based magnet in which the demagnetization rate at a high temperature can be inhibited even if the amount of heavy rare earth element(s) such as Dy and Tb is evidently decreased compared to the past or no such heavy rare earth element is used. The rare earth based magnet of the present invention is a sintered magnet which comprises RTB crystal grains as the main phases and the crystal boundary phases among RTB crystal grains. The microstructure of the sintered body is controlled by at least containing the first crystal boundary phases and the second crystal boundary phases, wherein the first crystal boundary phases contain at least R-T-M in the ranges of 20 to 40 atomic % for R, 60 to 75 atomic % for T and 1 to 10 atomic % for M, and the second crystal boundary phases contains at least R-T-M in the ranges of 50 to 70 atomic % for R, 10 to 30 atomic % for T and 1 to 20 atomic % for M.

Growing community of inventors

Tokyo, Japan

Yuki Nagamine