Electron magnetic resonance (EMR) measurements were employed for studying the magnetic state of La1−xCaxMnO3 crystalline samples with x=0.18, 0.20, and 0.22. It is shown that EMR spectra of La0.82Ca0.18MnO3 and La0.8Ca0.2MnO3 become drastically different from those of La0.78Ca0.22MnO3 below the Curie points of these compounds. Such spectra of La0.82Ca0.18MnO3 and La0.8Ca0.2MnO3 below TC are constituted of low-intensity doublet and relatively intense singlet signals attributed to ferromagnetic insulating and ferromagnetic metallic phases, respectively. The spectra of La0.78Ca0.22MnO3 have a shape of a broad asymmetric singlet signal similar to that observed in homogeneous ferromagnetic metallic manganites. The EMR data obtained on La1−xCaxMnO3 were compared with the recent results on magnetic, conductive, and nuclear magnetic resonance properties of these compounds and discussed in the context of transition from electronically separated phase to a homogeneous state with increasing Ca content.
|Journal||Physical Review B - Condensed Matter and Materials Physics|
|State||Published - 3 Nov 2003|