Magnetically correlated internal friction and Young’s modulus in La(Y)-Ca-Mn-O perovskites

Internal friction (Q^-1) and Young's modulus have been studied on a series of La_1-xCaₓMnO_3-δ and La0.6Y0.07Ca0.33MnO_3-δ polycrystals. A Q^-1 peak originating from the changes of the magnetic entropy is observed. The Q^-1 peak for x in the range of $0<x<0.5$ can be correlated with a transition from a paramagnetic (PM) disordered state to a ferromagnetic (FM) ordered state accompanied by a cooperative Jahn-Teller lattice distortion; from a PM insulator to a spin-glass insulator and accompanied with a large loss of modulus for $0.5<x<1.0;$ and the Q^-1 peak is ascribed to a transition from a PM to an AFM insulator for $x=1.0.$