An anomalous thermal expansion in the perovskite system, Gd1−xSrxMnO3 (0 ≤ x ≤ 0.3)

The thermal expansion behavior of sintered samples of Gd1−xSrxMnO3 (X = 0.0–0.4) was studied. The sintered bodies in this system showed negative thermal expansion over a wide temperature range. The detailed crystal structure refinements with respect to temperature showed that the volume of the orthorhombic perovskite lattice monotonically increased with temperature, however, in addition to this, the release of distortion from the Jahn-Teller effect of Mn3+ ion occurred over a wide temperature range, which brought the negative expansion of the a-axis, although the b- and c-axes increased with temperature. The anomalous thermal expansion is explained by the sum of the effects of the shrinkage of the a-axis and absorption of the b- and c-axesʹ expansion by the pores in the sintered body.