Thermal expansion of single-crystallineLa0.83Sr0.17MnO3: The importance of temperature-induced strain for the electrical resistivity

Thermal expansion, magnetization, and electrical-resistivity measurements of single crystalline ${\mathrm{La}}_{0.83}{\mathrm{Sr}}_{0.17}{\mathrm{MnO}}_3$ are presented. A first-order structural transition occurs at 300 K, transforming the high-temperature rhombohedral phase into an orthorhombic phase. The paramagnetic to ferromagnetic phase transition is second order and is clearly revealed as a change in slope of the linear-thermal expansion $\Delta l/l$ at $T_c=265\mathrm{}\mathrm{K}.$ The temperature derivative of $\Delta l/l$ yields the thermal-expansion coefficient α; thermodynamic analysis of α near $T_c$ reveals isotropic-uniaxial pressure derivatives of $T_c.$ Strain arising from the structural and magnetic transitions is shown to influence the electrical resistivity.