Effect of strain on the magnetic and transport properties of the composite manganites, La$_{2/3}$Ca$_{1/3}$MnO$_3$/yttria-stabilized zirconia

TL;DR

This study investigates how strain from yttria-stabilized zirconia affects the magnetic and transport properties of composite manganites, revealing strain as a key factor influencing these properties similarly to thin film effects.

Contribution

It demonstrates that strain effects from YSZ boundaries significantly influence magnetic and transport behaviors in bulk manganite composites, comparable to thin film phenomena.

Findings

TEP peak appears at low YSZ fractions during magnetic transition

Magnetic transition temperature varies with YSZ fraction, reaching a minimum at 4.5%

Strain from YSZ/LCMO boundary layer is identified as the main influencing factor

Abstract

The magnetic and transport properties have been investigated for the composite polycrystalline manganites, (1-x)$La_{2/3}Ca_{1/3}MnO_3$/(x)yttria-stabilized zirconia ((1-x)LCMO/(x)YSZ), at various YSZ fractions, x, ranging from 0 % to 15 %. The ac magnetic susceptibility, $\chi(T)$, DC magnetization, $M(T)$, temperature dependent resistivity, $\rho(T)$ and thermoelectric power (TEP), $S(T)$, have been measured. It was found, surprisingly, that a TEP peak showed up in the magnetic transition region for the sample with the x even as little as 0.75 %. The magnetic transition temperature reaches the minimum value as x increases from 0 % to 4.5 % and goes up as x increases further. Several possible factors such as the effect of strain, the finite size effect, and the effect of magnetic tunnelling coupling, {\it etc.}, in affecting the above physical properties of the composite manganites have been studied carefully. The strain induced by the YSZ/LCMO boundary layer (BL) was identified as the leading factor to account for the x dependence of these properties. It demonstrates that the effect of strain could be important in the bulk manganites as in the film sample.