Abstract: A semiconductor device includes semiconductor elements arranged in a first direction, an arm connection portion disposed between the semiconductor elements in the first direction, first and second power supply terminals disposed on the same side in the first direction, first and second substrates interposing the semiconductor elements therebetween, and a sealing body. The second substrate includes an insulating base member, a front-face metal body and a back-face metal body. The front-face metal body includes a second power supply wiring and a second relay wiring. The second power supply wiring includes a base portion on which the second element is arranged, and a pair of extending portions extending from the base portion in the first direction. The second relay wiring is disposed between the extending portions in a second direction, so that the second relay wiring and the base portion satisfy a relationship of L1<L2<L3.

Abstract: A ruthenium compound exhibits large negative thermal expansion. The ruthenium oxide is represented by the formula (1) Ca2?xRxRu1?yMyO4+z (wherein R represents at least one element selected from among alkaline earth metals and rare earth elements; M represents at least one element selected from among Sc, Ti, V, Cr, Mn, Fe, Co, Ni, Cu, Zn, and Ga; and the following relations are satisfied: 0?x<0.2, 0?y<0.3, and ?1<z<?0.02).

Abstract: A composite material of one aspect includes a resin matrix phase, and a ruthenium oxide having Ca2RuO4 structure and included in the resin matrix phase. The ruthenium oxide may be represented by a general formula (1): Ca2?xRxRu1?y1MyO4+z, in which R may represent at least one element selected from among alkaline earth metals and rare earth elements, M may represent at least one element selected from among Sc, Ti, V, Cr, Mn, Fe, Co, Ni, Cu, Zn, and Ga, and the values x, y, and z may satisfy 0?x<0.2, 0?y<0.3, and ?1<z<?0.02.

Abstract: A ruthenium compound exhibits large negative thermal expansion. The ruthenium oxide is represented by the formula (1) Ca2?xRxRu1?yMyO4+z (wherein R represents at least one element selected from among alkaline earth metals and rare earth elements; M represents at least one element selected from among Sc, Ti, V, Cr, Mn, Fe, Co, Ni, Cu, Zn, and Ga; and the following relations are satisfied: 0?x<0.2, 0?y<0.3, and ?1<z<?0.02).