Naslov
Influence of the synthesis method on structural and magnetic properties of doped lanthanum manganites

Autori
Žužić, Andreja ; Macan, Jelena ; Barišić, Dario ; Pajić, Damir

Vrsta, podvrsta i kategorija rada
Sažeci sa skupova, sažetak, znanstveni

Izvornik
1st ACDC 2023 Book of abstracts / Mandić, Vilko - Zagreb : Fakultet kemijskog inženjerstva i tehnologije Sveučilišta u Zagrebu, 2023, 39-39

ISBN
978-953-6470-99-0

Skup
1st International CroCerS (Croatian Ceramic Society) Conference thematically named 1st ACDC (Advanced Ceramics in Derivative Configurations) 2023

Mjesto i datum
Dubrovnik, Hrvatska, 26.04.2023. - 29.04.2023

Vrsta sudjelovanja
Predavanje

Vrsta recenzije
Međunarodna recenzija

Ključne riječi
lanthanum manganites ; magnetic properties ; magnetocaloric effect ; synthesis

Sažetak
Strontium-doped lanthanum manganites, described with the general formula La1-xSrxMnO3 (LSMO) are attractive, among others, for use in magnetic refrigeration and data storage due to their remarkable magnetic and electric properties at room temperature. In this study, LSMO powders were prepared by the citrate-nitrate autocombustion (CNA) and coprecipitation synthesis to investigate how the synthesis procedure impacts the structural characteristic of the materials. Both synthesis methods yielded materials with rhombohedral crystal structures. The lattice parameters and atoms occupancy factors were determined by Rietveld refinement analysis. The oxygen nonstoichiometry was determined by permanganate titration and the amount of Sr-dopant was confirmed by energy-dispersive X-ray spectroscopy. The obtained results showed that target Sr-doping was achieved and that materials prepared by coprecipitation possessed higher oxygen nonstoichiometry in comparison to the materials prepared by CNA. The magnetization curves as a function of temperature were recorded in a temperature range of 2-400 K at applied magnetic fields of 10 Oe, 100 Oe and 1000 Oe for all prepared materials. The Curie temperatures (TC) increased with increasing Sr-doping meaning that materials with x ≥ 0.2 are suitable for room-temperature applications as ferromagnets. Furthermore, Sr-doped materials showed low remanent magnetization making them applicable as soft ferromagnets. For materials prepared by coprecipitation, a large magnetic entropy change was observed near TC. The maximum entropy changes of 1.5 and 1.3 J kg-1 K-1 were observed for LSMO materials with x = 0.1 and 0.2 at temperatures of 381 K and ~400 K, respectively. These two materials had the highest oxygen nonstoichiometry leading to the increase of Mn4+/Mn3+ mixed valences ratio and overall crystal lattice entropy, accompanied by magnetic phase transitions around room temperature. Therefore, coprecipitation synthesis is presented as an efficient synthesis method of manganites leading to the structural defects, i.e., oxygen nonstoichiometry resulting in improved overall magnetic properties.

Izvorni jezik
Engleski

Znanstvena područja
Fizika, Kemijsko inženjerstvo

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