A sintered ferrite magnet comprises a main phase of an M type Sr ferrite having a hexagonal crystal structure. An amount of Zn is 0.05 to 1.35 mass % in terms of ZnO, the sintered ferrite magnet does not substantially include a rare-earth element (R), and the following Formula (1) is satisfied, where a total amount of Sr, Ba and Ca is M3 in terms of mol, a total amount of Fe, Co, Mn, Zn, Cr and Al is M4 in terms of mol, and an amount of Si is M5 in terms of mol.
0.5{M3(M4/12)}/M54.8(1).

The powder of the magnetoplumbite-type hexagonal ferrite is an aggregate of particles of a compound represented by Formula (1), and, in a particle size distribution based on number measured by a laser diffraction scattering method, in a case where a mode value is defined as a mode diameter, a diameter at a cumulative percentage of 10% is defined as D10 and a diameter at a cumulative percentage of 90% is defined as D90, the mode diameter is equal to or greater than 5 m and less than 10 m and an expression of (D90D10)/mode diameter3.0 is satisfied. In Formula (1), A represents at least one metal element selected from the group consisting of Sr, Ba, Ca, and Pb, and x satisfies 1.5x8.0.
AFe.sub.(12-x)Al.sub.xO.sub.19Formula(1)

The present invention relates to ferrite particles for bonded magnets and a resin composition for bonded magnets which can provide a bonded magnet molded product capable of realizing a high magnetic force and a complicated multipolar waveform owing to such a feature that the ferrite particles are readily and highly oriented against an external magnetic field in a flowing resin upon injection molding, as well as a bonded magnet molded product obtained by injection-molding the above composition. According to the present invention, there are provided ferrite particles for bonded magnets which have a crystallite size of not less than 500 nm as measured in an oriented state by XRD, and an average particle diameter of not less than 1.30 m as measured by Fisher method; a resin composition for bonded magnets; and a molded product obtained by injection-molding the composition.

An aspect of the present invention relates to ferromagnetic hexagonal ferrite powder, the average particle size of which is equal to or less than 20 nm, and which comprises, on a particle number basis, equal to or more than 50% of ellipsoid hexagonal ferrite powders satisfying relation (1):

1.2<major axis length/minor axis length<2.0(1).

A layered oxide material having a composition represented by Chemical Formula (1):

A.sub.wM.sup.j.sub.xM.sup.i.sub.yO.sub.2(1)

wherein A is sodium or is a mixed alkali metal including sodium as a major constituent; w>0; M.sup.j is a transition metal not including Ni or is a mixture of transition metals not including Ni; x>0; j1; M.sup.i includes either one or more alkali metals, one or more alkaline earth metals, or a mixture of one or more alkali metals and one or more alkaline earth metals; y>0; i1; and (M.sup.j+M.sup.i)3. A method of forming the layered oxide material includes the steps of mixing one or more precursors in a solvent to form a mixture; heating the mixture to form a reaction product; and cooling the reaction product under air or inert atmosphere.

A method for efficiently preparing ferrate based on nascent state interfacial activity. The method is as follows: (a) preparing nascent iron solution; (b) adding an oxidizing agent to the iron solution of step (a); (c) adding alkali solution or alkali particles to the mixed solution of step (b), mixing by stirring, and carrying out solid-liquid separation; (d) adding a stabilizing agent to the liquid separated out in step (c), and thus obtaining ferrate solution. The yield is 78-98%. The prepared ferrate solution is stable and can be stored for 3-15 days.

The method of manufacturing hexagonal ferrite powder includes preparing a hexagonal ferrite precursor by mixing an iron salt and a divalent metal salt in a water-based solution, and converting the hexagonal ferrite precursor into hexagonal ferrite within a reaction flow passage, within which a fluid flowing therein is subjected to heating and pressurizing, by continuously feeding a water-based solution containing the hexagonal ferrite precursor and gelatin to the reaction flow passage.

A hexagonal ferrite magnetic powder is significantly more useful for achieving simultaneously both the enhancement of the recording density and the enhancement of the SNR of a magnetic recording medium. The hexagonal ferrite magnetic powder contains Bi at a Bi/Fe molar ratio in a range of 0.035 or less, has a saturation magnetization s of 42.0 Am.sup.2/kg or more and a Dx volume calculated based on the crystallite diameters of 1,800 nm.sup.3 or less. A method for producing hexagonal ferrite magnetic powder includes a step of performing a treatment of immersing hexagonal ferrite magnetic powder containing Bi in a solution having dissolved therein a compound X that forms a complex with Bi, so as to elute a part of Bi existing in the hexagonal ferrite magnetic powder into the solution.

There is provided a radio wave absorbing composition containing a magnetic powder and a binder. There is also provided a radio wave absorber containing a magnetic powder and a binder. The magnetic powder is a powder of a substitution-type hexagonal ferrite subjected to surface treatment with a surface treatment agent, the surface treatment agent is a silicon-based compound, and the binder is an olefin-based resin.

A piezoelectric element includes a first electrode and a second electrode and a piezoelectric layer provided between the first electrode and the second electrode, the piezoelectric layer including a plurality of layers containing a composite oxide having a perovskite structure containing potassium, sodium, and niobium; wherein among the plurality of layers including the composite oxide, a first layer closest to the first electrode is preferred orientation in a first orientation, which is a {100} plane orientation in a film thickness direction, among the plurality of layers including the composite oxide, a second layer closest to the second electrode is, in an in-plane direction intersecting the film thickness direction, a mix of the first orientation and a second orientation, which is a {110} plane orientation, and is not preferred orientation in either the first orientation or the second orientation.