The structural-size effect, aging time, and pressure-dependent functional properties of Mn-containing perovskite nanoparticles

TL;DR

This study investigates how nanoparticle size, aging, and pressure influence the structural and magnetic properties of Mn-containing perovskite nanoparticles, revealing ways to tune their phase transition and magnetocaloric effects.

Contribution

First comprehensive analysis of the combined effects of size, aging, and pressure on Mn-perovskite nanoparticles' properties, providing insights for material tuning.

Findings

Smaller nanoparticles show the most significant structural changes over time.

Aging time strongly affects the Curie temperature in smaller nanoparticles.

Larger nanoparticles exhibit more stable phase transition temperatures after aging.

Abstract

The properties of nanoparticles are determined by their size and structure. When exposed to external pressure P, their structural properties can change. The improvement or degradation of the properties of the samples depending on time is particularly interesting. The knowledge of the influence of structural-size effect, aging time, and pressure on the behavior of the compounds is essential for fundamental and applied purposes.Therefore, the first attempts have been made to shed light on how the functional properties of the Mn-containing perovskites change depending on them. The nanoparticles of different sizes, from 20 to 70 nm, have been obtained. After 3 years, their structural properties underwent significant changes, including an increase in particle size, bandwidth, and microstrains, as well as a reduction in dislocation density.The greatest change in the structure is observed for the smallest nanoparticles. The phase transition temperatures increase with nanoparticle size, time, and pressure. The aging time has the strongest influence on the changing Curie temperature for the smallest and most magnetically inhomogeneous nanoparticles with dTc/dP = 100 K / GPa. Conversely, the structural-size effect and external pressure have the greatest influence on the biggest and most magnetically uniform nanoparticles with dTc/dP = 91 and 16 K / GPa, respectively. After 3 years, the biggest nanoparticles demonstrate the most stable phase transition temperatures with improved magnetocaloric parameters near room temperature. These structural-size effect, aging time, and pressure are powerful instruments to tune the phase transition temperatures and magnetocaloric effect of the nanoparticles. These outcomes may have implications for the whole class of perovskites and could initiate a new mainstream.