Structural phase transitions and sound velocity anomalies in La(1-x)Sr(x)MnO3

TL;DR

This study measures how sound velocities in La(1-x)Sr(x)MnO3 manganites vary with temperature, revealing correlations with magnetic and structural phase transitions, including sharp and smooth changes linked to different compositions.

Contribution

It provides detailed experimental data on sound velocity anomalies across various phase transitions in La(1-x)Sr(x)MnO3, highlighting the relationship between structural, magnetic, and vibrational properties.

Findings

Sharp increases in V(T) at rhombohedral-orthorhombic transitions.

Deep minima in V(T) at Jahn-Teller related phase changes.

Correlation of V(T) behavior with magnetic susceptibility and magnetization.

Abstract

The sound velocities dependencies on temperature V(T) were measured by means of resonance method have on the thin plates of quasimonocrystalline manganites La(1-x)Sr(x)MnO3. Results are presented for x=0.1, 0.125, 0.15, 0.175 and 0.2 in the temperature range from 70 to 350K. The V(T) behavior correlates with those of susceptibilities and magnetic moment M(T). For x=0.175 and 0.2 the transition to ferromagnetic state is accompanied by appearance of large but smooth rise in V(T) whereas structural phase transition between the rhomboedral (R) and orthorhombic (O) structures is accompanied by sharp increase up to 15-20% in V(T). For x=0.1, 0.125 and 0.15 the structural phase transition between Jahn-Teller distorted orthorhombic structure (O') and pseudocubic one (O'') is accompanied by deep minimum (~20-30%) in V(T).