Magnetic Correlations and Spin Dynamics in Crystalline La$_{1-x}$Ca $_{x}$MnO$_{3}\ (x = 0, 0.1, 0.2, 0.3)$: Analysis of Basic EPR Parameters

Electron paramagnetic resonance data of La
_1-x
Ca
_x
MnO
₃
compounds with x=0,0.1,0.2,0.3 were analyzed in order to explore the changes in effective spin-spin interactions and spin dynamics parameters. The presence of two magnetic subsystems - host of superexchange coupled Mn
³⁺
ions and Mn
⁴⁺
associated clusters is characteristic for x=0 and 0.1 samples, while ferromagnetically correlated host is observed in x=0.2 and 0.3 ones. The contributions of both ionic host and doped carriers to spin relaxation parameters were determined using general spin-dynamics theory.