Thermal expansion of single-crystalline La0.83Sr0.17MnO3: The importance of temperature-induced strain for the electrical resistivity

Thermal expansion, magnetization, and electrical-resistivity measurements of single crystalline La0.83Sr0.17MnO3 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 Δl/l at Tc=265K. The temperature derivative of Δl/l yields the thermal-expansion coefficient α; thermodynamic analysis of α near Tc reveals isotropic-uniaxial pressure derivatives of Tc. Strain arising from the structural and magnetic transitions is shown to influence the electrical resistivity. copyright 1999 The American Physical Society