Effect of rare earth ions on transition temperature in perovskite materials by on-line ultrasonic studies

Abstract

On-line measurements of ultrasonic longitudinal velocity, shear velocity and longitudinal attenuation were carried out on R 1-x Sr x MnO 3 perovskites (R = La, Pr, Nd and Sm) for different compositions of Sr, at a fundamental frequency of 5 MHz over wide range of temperatures using the through-transmission method. The observed maxima/minima in velocities and attenuation have been discussed with decrease in ionic radii and composition. As a decrease in the ionic radii of rare earth elements leads to a decrease in transition temperature (T c ), the results that are observed show that measurement is one of the best tools to explore the structural/phase transition on-line velocity in perovskite manganese materials as a function of the ionic radii of rare earth elements.

Structure–Property Relations in Rare-Earth Doped Manganite Perovskites: A Review

“…Monitoring oxygen content in perovskite oxides is one of the most crucial steps for tuning their functionality because there are strong relationships between electrons, spins and lattices-stemming from strong hybridization between transition metal d and oxygen p orbitals. Thus, tuning of the crystal structure of perovskite will help to modify the properties of materials for advanced technological applications [43][44][45].…”

Структура и электропроводность перовскитов Pr-=SUB=-1-x-=/SUB=-Sr-=SUB=-x-=/SUB=-MnO-=SUB=-3-=/SUB=- (x=0; 0.15; 0.25)

“…Величина ян-теллеровского искажения при допировании манганитов зависит от разницы между ионными радиусами редкоземельного металла и допанта. Варьирование редкоземельного металла в составе манганитов оказывает влияние на их термодинамическую стабильность, структурные и физические свойства [16][17][18]. Так катоды стронциевых манганитов на основе лантана показывают достаточно высокую электропроводность, но при использовании празеодима электропроводность понижается [18].…”