Abstract: The present invention provides a lanthanum sulfide or cerium sulfide sintered compact usable as a thermoelectric conversion material having a high Seebeck coefficient. The sintered compact has a chemical composition of La2S3 or Ce2S3, and a crystal structure consisting of a mixture of beta and gamma phases having a Seebeck coefficient higher than that of the crystal structure otherwise being in gamma single-phase. The sintered compact is produced by preparing a beta-phase La2S3 or alpha-phase Ce2S3 powder of raw material having a high purity with a suppressed carbon impurity concentration and a given range of oxygen concentration, charging the raw material into a carbon die having an inner surface covered with an h-BN applied thereon, and hot-pressing the charged material under vacuum to form a mixture of beta and gamma phases having a high Seebeck coefficient.

Abstract: A high-dielectric material which is especially useful as a material for a high-capacitance capacitor and which has a high dielectric constant is provided. The high-dielectric material is composed of a sintered body of a rare-earth sulfide, the high-dielectric material having a crystal structure of tetragonal ? type, a chemical composition represented by Ln2S3 (where Ln represents a rare-earth metal), a frequency domain within the range of 0.5 kHz to 1,000 kHz, and a value of relative dielectric constant of more than 1,000 at room temperature.

Abstract: A cooling device for a heat-generating electronic component such as a semiconductor integrated circuit element is provided. In particular, a cooling device using a thermoelectric conversion material is provided. A cooling device for an electronic component includes a thermoelectric conversion material disposed between two electrodes that function as a cathode and an anode and are electrically short-circuited. The thermoelectric conversion material is either a p-type material or an n-type material or a combination of p-type and n-type materials arranged alternately in series. This cooling device is brought into contact with an electronic component requiring cooling so that one electrode side in contact with the thermoelectric conversion material becomes a low-temperature side and the other electrode side becomes a high-temperature side.