Mn Site Substitution Of La0.67Ca0.33MnO3 With Closed Shell Ions: Effect on Magnetic Transition Temperature

TL;DR

This study investigates how substituting Mn with closed shell and magnetic ions affects the magnetic and metal-insulator transition temperatures in La0.67Ca0.33MnO3, revealing suppression effects due to lattice disorder and magnetic interactions.

Contribution

It provides new insights into how different ion substitutions influence transition temperatures without altering crystal symmetry or oxygen stoichiometry.

Findings

Substitutions suppress transition temperatures to varying degrees.

Lattice disorder and magnetic coupling are key factors in transition suppression.

Magnetic and non-magnetic substitutions have distinct effects on properties.

Abstract

Mn site is substituted with closed shell ions (Al, Ga. Ti, Zr and a certain combination of Zr and Al) and also with Fe and Ru ions carrying the magnetic moment (S=5/2 and 2 respectively) at a fixed concentration of 5 at. %. Substitution did not change either the crystal symmetry or the oxygen stiochiometry. All substituents were found to suppress both the metal-insulator and ferromagnetic transition temperatures (TP(r) and TC respectively) to varied extents. Two main contributions identified for the suppression are the lattice disorder arising due to difference in the ionic radii (rMn3+-rM) between the substituent (rM) and the Mn3+ ion (rMn3+) and in the case of the substituents carrying a magnetic moment, the type of magnetic coupling between the substituent and that of the neighboring Mn ion.