LAUSR

Abstract Detailed analysis of the temperature dependent dc susceptibility data shows the modification from the Griffiths like phase (GP) to non-Griffiths like phase (non-GP) in ( La 1 - x Y x ) 0.7 Ca 0.3 MnO 3 ( x = 0 , 0.3 , 0.4 , 0.5 , 0.6 ) compounds with x . The existence of non-Griffiths phase is revealed from the upward deviation of the inverse susceptibility (1/ χ ) versus temperature plot from the Curie-Weiss behavior for the compounds with x ⩾ 0.5 . Whereas Griffiths phase is identified from the downturn of 1 / χ versus T plot from the Curie-Weiss line in the compounds with x = 0.3 , 0.4 . The increased lattice distortion (with x ) decreases the M - O - Mn bond angle and at the same time increase the electron-phonon (e-ph) coupling which in turn decreases the ferromagnetic double exchange (DE) interactions and enhances the effective short-range antiferromagnetic superexchange interactions between Mn 3 + / Mn 3 + and Mn 4 + / Mn 4 + ions above the Curie temperature ( T C ). The enhancement of this short-range antiferromagnetic (SR-AFM) interactions have been attributed to the conversions from GP to non-GP phase. The increased SR-AFM interactions with Y doping has also been substantiated from the magnetocaloric study.