PRESSURE EFFECT ON THE DOUBLE-EXCHANGE FERROMAGNET LA1-XSRXMNO3 (0.15-LESS-THAN-OR-EQUAL-TO-X-LESS-THAN-OR-EQUAL-TO-0.5)

The effect of hydrostatic pressure on the magnetic and electronic properties has been investigated for prototypical double-exchange ferromagnets, La1-xSrxMnO3, with varying nominal hole concentration x (0.15≤x≤0.5). A pressure-enhanced transfer interaction is observed to stabilize the ferromagnetic metallic phase, i.e., increase the Curie temperature TC, over the whole concentration range investigated. The pressure coefficient of TC is found to be significantly x dependent and steeply decreases from d lnTC/dP+0.065 GPa-1 at x=0.15 to a small value (+0.005 GPa-1) at x=0.4-0.5. This suggests a symptomatic change of the electronic nature from the strong- to weak-coupling region with increasing the hole-doping level. © 1995 The American Physical Society.