Low-field magnetic properties as indication of disorder, frustration and cluster formation effects in La₁₋xCaxMn₁₋yFeyO₃

yesLow-field (B=2–80 G) DC magnetic susceptibility, χ, is investigated in ceramic La₁₋xCaxMn₁₋yFeyO₃ (LCMFO) samples with x=0.3. When y is increased from 0 to 0.1 the ferromagnetic (FM) Curie temperature, TC, decreases from 259 to 107 K, indicating growth of disorder by iron doping. A transformation of LCMFO from a weakly frustrated FM phase between y≈0–0.05 to a strongly frustrated mixed, FM and glassy, phase between y≈0.07–0.10 is revealed by measurements of magnetic irreversibility and long-time (up to t=105 s) relaxation of thermoremanent magnetizationBelgorod State Universit