Disclosed herein are ceramic materials, such as bismuth substituted garnets, which can have high curie temperatures and high dielectric constants. In certain implementations, indium can be incorporated into the ceramic to improve certain properties and to avoid calcium compensation. The ceramic materials disclosed herein can be particular advantageous for below resonance applications.

A single-crystalline LnBM.sub.2O.sub.5+ or LnBM.sub.2O.sub.5.5+ compound is provided, which includes an ordered oxygen vacancy structure; wherein Ln is a lanthanide, B is an alkali earth metal, M is a transition metal, O is oxygen, and 01. Methods of making and using the compound, and devices and compositions including same are also provided.

Disclosed are a mixed oxide composition based on zirconium and cerium exhibiting a high reducibility, the process for preparing it and its use in the field of catalysis.

Disclosed are embodiments of synthetic garnet materials for use in radiofrequency applications. In some embodiments, increased amounts of gadolinium can be added into specific sites in the crystal structure of the synthetic garnet by incorporating indium, a trivalent element. By including both indium and increased amounts of gadolinium, the dielectric constant can be improved. Thus, embodiments of the disclosed material can be advantageous in both above and below resonance applications, such as for isolators and circulators.

Disclosed herein are ceramic materials, such as bismuth substituted garnets, which can have high curie temperatures and high dielectric constants. In certain implementations, indium can be incorporated into the ceramic to improve certain properties and to avoid calcium compensation. The ceramic materials disclosed herein can be particular advantageous for below resonance applications.

The present invention provides a ferrite sintered magnet comprising (1) main phase grains containing a ferrite having a hexagonal structure, (2) two-grain boundaries formed between two of the main phase grains, and (3) multi-grain boundaries surrounded by three or more of the main phase grains. The above ferrite sintered magnet comprises Ca, R, Sr, Fe and Co, with R being at least one element selected from the group consisting of rare earth elements and Bi, and comprising at least La. The number Nm of the above main phase grains and the number Ng of the above multi-grain boundaries in the cross section including the direction of the easy magnetization axis of the above ferrite sintered magnet satisfy the formula (1A):

50%Nm/(Nm+Ng)65%(1A).

There is provided a ferrite sintered magnet having a high residual magnetic flux density.

A ferrite sintered magnet 2 includes a plurality of main phase particles 5 including ferrite having a hexagonal structure, the number of core-shell structured particles 5A having a core 7 and a shell 9 covering the core 7, among the main phase particles 5, is smaller than the number of the main phase particles 5 other than the core-shell structured particles 5A.

According to one embodiment, an active material is provided. The active material includes a lithium niobium composite oxide represented by a general formula Li.sub.xFe.sub.1yM1.sub.yNb.sub.112M2.sub.zO.sub.29 (1) and having an orthorhombic crystal structure. In the general formula (1), 0x23, 0y1 and 0<z6 are satisfied. Each of M1 and M2 independently includes at least one element selected from a group consisting of Fe, Mg, Al, Cu, Mn, Co, Ni, Zn, Sn, Ti, Ta, V, and Mo.

This ferrite magnet has a ferrite phase having a magnetoplumbite structure, and an orthoferrite phase, and is characterized in that the composition ratios of the total of each metal element A, R, Fe and Me is represented by expression (1) A.sub.1-xR.sub.x(Fe.sub.12-yMe.sub.y).sub.z, (in expression (1), A is at least one element selected from Sr, Ba, Ca and Pb; R is at least one element selected from the rare-earth elements (including Y) and Bi, and includes at least La, and Me is Co, or Co and Zn) and in that the content (m) of the orthoferrite phase is 0<m<28.0 in mol %. The invention makes it possible to achieve a ferrite magnet with increased Br.

A bismuth-substituted rare earth iron garnet single crystal suitable for Faraday rotators and optical isolators with reduced insertion loss due to suppressed valence fluctuation of Fe ions is provided. The bismuth-substituted rare earth iron garnet single crystal of the present invention is characterized by the composition formula (Tb.sub.aLn.sub.bBi.sub.cMg.sub.3?(a+b+c))(Fe.sub.dGa.sub.eTi.sub.fPt.sub.5?(d+e+f))O.sub.12. In the composition formula above, 0.02?f?0.05, 0.02?{3?(a+b+c)}?0.08, and ?0.01?{3?(a+b+c)}?{f+5?(d+e+f)}?0.01. Ln is a rare earth element and may be selected from Eu, Gd, Ho, Tm, Yb, Lu, and Y.