Investigation on the low-frequency mechanical properties of La 0.6Sr 0.4Co 1− xFe xO 3− δ materials

Abstract

The low-frequency mechanical properties of La 0.6Sr 0.4Co 1− x Fe x O 3− δ (0 ≤ x ≤ 0.8) materials have been measured using a computer-controlled pendulum. For undoped sample, five internal friction peaks (P0, P1, P2, P3 and P4) were observed. However, with the Fe doping, only two peaks (P3 and P4) were found at high temperature. The peaks of P0 and P1 have the feature of phase transition-induced internal friction, while the peaks of P2, P3 and P4 are the relaxation-type. From the analysis, it is suggested that the peak of P0 is due to the phase separation and the peak of P1 is related to the ferromagnetic (FM)–paramagnetic (PM) phase transition. For the peaks of P2, P3 and P4, they were associated with the motion of domain walls. The formation of this kind of domain structure is a consequence of a transformation from the paraelastic cubic phase to ferroelastic rhombohedral phase.