Influence of pressure on structural and magnetic phase transitions inLa0.835Sr0.165MnO3

Measurements of the thermal expansion of a single crystal of ${\mathrm{La}}_{0.835}{\mathrm{Sr}}_{0.165}{\mathrm{MnO}}_3$ were performed under hydrostatic pressure of up to 9 kbar. The $P$-$T$ phase diagram is established for the structural and magnetic phase transitions. Pressure is found to enhance the ferromagnetic coupling and to weaken the stability of the low-temperature orthorhombic phase by reducing the bending of the Mn-O-Mn bond. The decrease in the temperature $T_S$ of the structural phase transition and the increase in the Curie temperature with increasing pressure leads to the two phase boundaries crossing at a pressure of about 3 kbar. The peculiar behavior of the $T_S$ and $T_C$ in the vicinity of the crossing point demonstrates a strong coupling between structural distortion and magnetic ordering in the ${\mathrm{La}}_{0.835}{\mathrm{Sr}}_{0.165}{\mathrm{MnO}}_3$ compound.