Ferromagnetic and transport properties of La0.8Ca0.2MnO3 and La0.78Ca0.22MnO3 single crystals were studied in temperature range 4.2 K<T<300 K and under hydrostatic pressure up to 12 kbar. It was found that the above compounds exhibit different shifts of Curie temperatures TC under pressure. For La0.8Ca0.2MnO3 dTC/dP≈0.3 K/kbar, whereas for La0.78Ca0.22MnO3 a stronger nonlinear increase TC(P) was observed. A significant change of the easy axis magnetization with temperature was found for La0.8Ca0.2MnO3, in the (110) plane. The above effect is almost entirely suppressed by an external pressure of 6 kbar. The ac susceptibility of La0.8Ca0.2MnO3 shows a sharp frequency dependent increase at T = 80 K, upon heating indicating a transition to cluster spin-glass formation. The results observed are discussed regarding a coexistence of ferromagnetic metallic and ferromagnetic insulating phases.
|Number of pages||6|
|Journal||Physical Review B - Condensed Matter and Materials Physics|
|State||Published - 1 Jan 2002|