Abstract
Lanthanum calcium based perovskites are found to be advantageous for the possible applications in magnetic sensors/reading heads, cathodes in solid oxide fuel cells, and frequency switching devices. In the present investigation La0.3Ca0.7MnO3 perovskites were synthesised through solid state reaction and sintered at four different temperatures such as 900, 1000, 1100 and 1200˚ C. X-ray powder diffraction pattern confirms that the prepared La0.3Ca0.7MnO3 perovskites have orthorhombic structure with Pnma space group. Ultrasonic in-situ measurements have been carried out on the La0.3Ca0.7MnO3 perovskites over wide range of temperature and elastic constants such as bulk modulus of the prepared La0.3Ca0.7MnO3 perovskites was obtained as function of temperature. The temperature-dependent bulk modulus has shown an interesting anomaly at the metal-insulator phase transition. The metal insulator transition temperature derived from temperature-dependent bulk modulus increases from temperature 352˚ C to 367˚ C with the increase of sintering temperature from 900 to 1200˚ C.
Highlights
Mixed-valent R1-xAxMnO3 perovskite manganites (R- Rare earth element and A- Alkaline element) are of great importance due to their special properties such as colossal magneto resistance (CMR), ferromagnetic (FM) to paramagnetic (PM) phase transition, metal-insulator (MI) phase transition charge ordering (CO), etc [1]
X-ray diffraction (XRD) spectra of the prepared LCMO900, LCMO1000, LCMO1100 and LCMO1200 perovskite was shown in Fig.1 which shows that the samples belong to orthorhombic crystal structure with pnma space group
The crystalline size of the prepared samples as determined by Scherrer’s equation [7] are 52±3, 60±4, 71±3, 78±3 nm for the samples LCMO900, LCMO1000, LCMO1100 and LCMO1200 respectively and it reveals that the crystalline size increases with the increase of sintering temperature of the sample
Summary
Mixed-valent R1-xAxMnO3 perovskite manganites (R- Rare earth element and A- Alkaline element) are of great importance due to their special properties such as colossal magneto resistance (CMR), ferromagnetic (FM) to paramagnetic (PM) phase transition, metal-insulator (MI) phase transition charge ordering (CO), etc [1]. The applications of such materials include solar cells, switching devices, and magnetic storage devices. By changing the doping element, its level and its ionic radii one can modify the properties of the perovskite materials.
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