Abstract: [Technical Problem] It is an object to provide a device for a single-crystal growth and a method of a single-crystal growth in which even when materials that are different in, for example, a melting point or a diameter are to be grown, the conditions for the stable growth of a single crystal can be obtained and a high-quality single crystal having a desired diameter can hence be grown. In addition, the device and the method have a reduced fluctuation of heating intensity to facilitate a crystal growth. [Solution of Problem] A device for a single-crystal growth is provided with a raw material rod (14) that is supported by an upper crystal driving shaft (8), a seed crystal rod (16) that is supported by a lower crystal driving shaft (12), and a heating means, and a contact part of the raw material rod (14) with the seed crystal rod (16) is heated with a heating means to form a melting zone (18) and grow a single crystal.

Abstract: A manganese oxide material has MnO.sub.3 as a matrix. It is an antiferromagnetic insulator and, when subjected to an electrical current or electric field, it is transformed into a ferromagnetic metal.

Abstract: A manganese oxide material that can be used as a switching device or as a memory device or the like is formed of Mn-based oxide material. The Mn-based oxide material exhibits insulator-to-metal transitions induced by irradiating the material with laser light.

Abstract: A magnetoresistor with an ordered double perovskite structure is an oxide crystal which has an ordered double perovskite crystal structure represented by the general formula of A.sub.2 BB'O.sub.6, wherein A stands for Sr atoms, B for Fe atoms and B' for Mo or Re atoms and wherein the Fe atoms and the Mo or Re atoms are alternately arranged and which exhibits negative magnetoresistive characteristics.

Abstract: Proposed is a grain boundary-free crystalline body of a perovskite structure having a chemical composition of the formula Pr.sub.1-x M.sub.x MnO.sub.3, in which M is calcium or strontium and the subscript x is a number of 0.3 to 0.5, which exhibits a magnetoresistance behavior with a phase transition between an insulator phase and a ferromagnetic metallic phase accompanied by the phenomenon of hysteresis. This grain boundary-free crystalline body can be obtained by subjecting a sintered body of a powder blend consisting of the oxides of praseodymium, manganese and calcium or strontium to a crystal growing treatment by the floating zone-melting method in an atmosphere of oxygen.