Structural and magnetic properties of $La_{0.67}Ca_{0.33}MnO_3$ (D = Ca, Sr, Ba) manganites prepared by Ball milling

TL;DR

This study synthesizes and characterizes LaCa, LaBa, and LaSr manganites, revealing their structural phases and magnetic behaviors, with notable ferromagnetism in LaSr and LaBa samples at room temperature.

Contribution

It provides detailed structural and magnetic analysis of LaCa, LaBa, and LaSr manganites prepared by ball milling and sintering, highlighting phase purity and magnetic properties.

Findings

LaCa is paramagnetic at room temperature.

LaSr exhibits soft ferromagnetism with Tc = 380 K.

LaBa shows ferromagnetism with Tc = 343 K, enhanced by higher sintering temperature.

Abstract

In this research, we report on the synthesis and characterization of $La_{0.67}Ca_{0.33}MnO_3$ (LCMO), $La_{0.67}Ba_{0.33}MnO_3$ (LBMO), and $La_{0.67}Sr_{0.33}MnO_3$ (LSMO) perovskites. Precursor powders for the perovskite samples were prepared using ball mailing technique. The resulting powder was pressed into disks which were subsequently sintered at 1000 C for 2h. The structural characteristics of the prepared samples were investigated using X-ray diffraction (XRD) and scanning electron microscope (SEM), and the magnetic properties were investigated using vibrating sample magnetometry (VSM). XRD pattern of LCMO sample revealed a pure perovskite phase with Pnma space group, while the pattern of LSMO sample revealed a pure perovskite with R3c$^-$ space group. XRD pattern of LBMO sample, however, demonstrated the presence of a major perovskite phase with R3c$^-$ symmetry, together with a secondary $BaMnO_3$ phase. This secondary phase disappeared upon sintering LBMO at a higher temperature of 1100 C. Isothermal magnetic measurements and thermomagnetic curves revealed that LCMO was paramagnetic at room temperature. However, LSMO exhibited soft ferromagnetic behavior at room temperature, with Tc = 380 K and Ms = 50.9 emu/g. Also, LBMO sample sintered at 1000 C exhibited soft ferromagnetic behavior at room temperature, with Curie temperature Tc = 343 K and a rather low saturation magnetization of Ms = 30.7 emu/g. The higher sintering temperature of LBMO compound resulted in a significant increase of the saturation magnetization to 50.8 emu/g for the sample sintered at 1100 C.