SUBSTANTIAL PRESSURE EFFECTS ON THE ELECTRICAL-RESISTIVITY AND FERROMAGNETIC TRANSITION-TEMPERATURE OF LA1-XCAXMNO3

The influence of hydrostatic pressure on the electrical resistivity rh o and ferromagnetic transition temperature T-c of La1-xCaxMnO3 is pres ented for x = 0.21, 0.33, and 0.40. Pressure strongly decreases rho an d drives T-c up at rates as large as +37 WGPa for the x=0.21 specimen; this is significantly larger than dT(c)/dP values observed in convent ional ferromagnets and about eight times larger than dT(N)/dP observed in Ca1-xSrxMnO3 antiferromagnets. The transport mechanism in these ox ides is influenced in a qualitatively similar way by both pressure and magnetic field. The results are interpreted in the framework of the d ouble-exchange interaction involving conduction via magnetic polarons.