Provided is a method that allows growing a single crystal of silicon carbide on an off-substrate of silicon carbide while suppressing surface roughening. The method for producing a crystal of silicon carbide includes rotating a seed crystal of silicon carbide while bringing the seed crystal into contact with a starting material solution containing silicon and carbon. A crystal growth surface of the seed crystal has an off-angle, and the position of a rotation center of the seed crystal lies downstream of the central position of the seed crystal in a step flow direction that is a formation direction of the off-angle.

A method for producing a Group III nitride crystal includes: preparing a protective layer on a region except for an epitaxial growth surface of an RAMO.sub.4 substrate containing a single crystal represented by the general formula RAMO.sub.4 (wherein R represents one or a plurality of a trivaient element selected from a group of elements including: Sc, In, Y, and a lanthanoid element, A represents one or a plurality of a trivalent element selected from a group of elements including: Fe(III), Ga, and Al, and M represents one or a plurality of a divalent element selected from a group of elements including: Mg, Mn, Fe(II), Co, Cu, Zn, and Cd); and forming a Group III nitride crystal on the epitaxial growth surface of the RAMO.sub.4 substrate by a flux method.

A silicon-based molten composition according to an exemplary embodiment is used in a solution growing method for forming a silicon carbide single crystal, includes silicon (Si), yttrium (Y), and iron (Fe), and is expressed in Formula 1.

Si.sub.aY.sub.bFe.sub.c [Formula 1] In Formula 1, the a is equal to or greater than 0.4 and equal to or less than 0.8, the b is equal to or greater than 0.2 and equal to or less than 0.3, and the c is equal to or greater than 0.1 and equal to or less than 0.2.

A low-resistance p-type SiC single crystal containing no inclusions is provided. A method for producing a SiC single crystal in which a SiC seed crystal substrate is contacted with a SiC solution having a temperature gradient such that a temperature of the SiC solution decreases from an interior of the SiC solution toward a surface of the SiC solution, to grow the SiC single crystal, wherein the SiC solution comprises Si, Cr, Al and B, and wherein the Al is comprised in the SiC solution in an amount of 10 at % or greater, based on the total of the Si, Cr, Al and B, and the B is comprised in the SiC solution in an amount of greater than 0.00 at % and no greater than 1.00 at %, based on the total of the Si, Cr, Al and B.

A preparation method and application of a Na.sub.3Ba.sub.2(B.sub.3O.sub.6).sub.2F birefringent crystal, the crystal having a chemical formula of Na.sub.3Ba.sub.2(B.sub.3O.sub.6).sub.2F, and belonging to a hexagonal crystal system, the space group being P6.sub.3/m, and the lattice parameters comprising a=7.3490(6) , c=12.6340(2) , V=590.93(12) .sup.3, Z=2; the crystal is used for an infrared/deep ultraviolet waveband, and is an uniaxial negative crystal, n.sub.e<n.sub.o, the transmission range being 175-3,350 nm, the birefringence of 0.090 (3,350 nm)-0.240 (175 nm), and the crystal being grown by employing a melting method or a flux method; the crystal prepared via the method has a short growth cycle, high crystal quality and large crystal size, is easy to grow, cut, polish and store, is stable in the air, and difficult to deliquesce, and can be used for preparation of various polarization beam polarization beam splitter prism and infrared/deep ultraviolet waveband optical communication elements.

Provided is a SiC single crystal that has a large growth thickness and contains no inclusions. A SiC single crystal grown by a solution process, wherein the total length M of the outer peripheral section formed by the {1-100} faces on the {0001} growth surface of the SiC single crystal, and the length P of the outer periphery of the growth surface of the SiC single crystal, satisfy the relationship M/P0.70, and the length in the growth direction of the SiC single crystal is 2 mm or greater.

A method of producing a crystal includes a step of preparing a solution containing carbon and a silicon solvent, and a seed crystal of silicon carbide; a step of contacting a lower face of the seed crystal with the solution; a step of raising a temperature of the solution to a first temperature zone; a step of relatively elevating the seed crystal with respect to the solution in a state where a temperature of the solution is being lowered from the first temperature zone to a second temperature zone; a step of raising a temperature of the solution from the second temperature zone to the first temperature zone; and a step of relatively elevating the seed crystal with respect to the solution in a state where a temperature of the solution is being lowered from the first temperature zone to the second temperature zone.

Provided are a Faraday rotator having a high light transmittance and a high Verdet constant and an optical isolator using the same. The Faraday rotator of the present invention contains a garnet type crystal represented by (Tb.sub.3-x-yR.sub.xBi.sub.y)Al.sub.5O.sub.12 (R represents one or more elements selected from Y, Er, Yb, or Lu, 0<x, and 0y). It is preferable that the Faraday rotator contains a garnet type crystal represented by (Tb.sub.3-x-yR.sub.xBi.sub.y)Al.sub.5O.sub.12 (R is one or more elements selected from Y or a lanthanoid (La, Ce, Pr, Nd, Pm, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb, or Lu), 0x, and 0<y)).

Provided are a practical method for manufacturing TAG single crystal. The method of manufacturing a garnet type crystal brings a raw material solution into contact with a substrate formed of a Y.sub.3Al.sub.5O.sub.12 crystal or a Dy.sub.3Al.sub.5O.sub.12 crystal and performs liquid phase epitaxial growth. The garnet type crystal is represented by (Tb.sub.3-x-yR.sub.xBi.sub.y) Al.sub.5O.sub.12 (R is one or more elements selected from Y or a lanthanoid (La, Ce, Pr, Nd, Pm, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb, or Lu), 0x, and 0y)).

A p-type SiC single crystal having lower resistivity than the prior art is provided. This is achieved by a method for producing a SiC single crystal in which a SiC seed crystal substrate is contacted with a SiC solution having a temperature gradient such that the temperature decreases from the interior toward the surface, to grow a SiC single crystal, the method comprising: using as the SiC solution a SiC solution containing Si, Cr and Al, wherein the Al content is 3 at % or greater based on the total of Si, Cr and Al; and contacting a (0001) face of the SiC seed crystal substrate with the SiC solution to grow a SiC single crystal from the (0001) face.