abstract
In this work, the impact of La doping on structural and magnetic properties of a(1-)(x)La(x)Fe(0.5)Mn(0.5)O(3-delta) (0.05 <= x 0.15) elaborated using the solid-state method has been investigated in details by X-ray diffraction and magnetic measurements. Structural analysis showed that all the phases crystallize in the cubic system with a Pm-3m space group. The electron density (ED) study revealed that Mn/Fe-O and Ca/La-0 form partial covalent and ionic bonds, respectively, in the unit cell. Importantly, the ED plots show also the formation of an alternate ordered arrangement of oxygen elements and their vacancies. The magnetic study revealed that all our investigated phases exhibit a paramagnetic (PM)-antiferromagnetic (AFM) transition. The decrease in Ned temperature (T-N) with increasing x can be explained by the enhancement of ferromagnetic (FM) magnetic interactions due to La doping. Non-null magnetization and the magnetic hysteresis loop at room temperature confirm the presence of weak ferromagnetism in the PM region. These materials also have complex magnetic responses below T-N, which are related to the formation of a variety of magnetic exchange interactions within the system, including AFM, FM and ferrimagnetic (FiM) ordering. As a result, exchange coupling between FM/FiM moments and the antiphase boundaries of AFM explains the observed exchange bias in the compounds. Given the practical applications of perovskites, the current observation of the exchange bias effect and ambient temperature ferromagnetism in these materials may be of major technological significance. [GRAPHICS] .
keywords
EXCHANGE BIAS; CHARGE DISPROPORTIONATION; MAGNETOCALORIC PROPERTIES; OXYGEN DEFICIENCY; MANGANITES; DISORDER; BEHAVIOR; PHASE; CRYSTAL
subject category
Materials Science; Physics
authors
Selmi, R; Cherif, W; Khammassi, F; Sarabando, AR; Ferreira, NM
our authors
Artur Ricardo Mesquita Sarabando
research granteGroups
acknowledgements
This paper within the framework of collaboration is supported by the Tunisian Ministry of Higher Education and Scientific Research and the Portuguese Ministry of Science, Technology and Higher Education. The authors acknowledge the i3N (UID/CTM/50025/2020) and CICECO-Aveiro Institute of Materials (UID/CTM/50011/2020), financed by FCT/MEC and FEDER under the PT2020 Partnership Agreement. This work is also funded by national funds (OE), through FCT - FundacAo para a Ciencia e a Tecnologia, I.P., in the scope of the framework contract foreseen in the numbers 4, 5 and 6 of the article 23, of the Decree-Law 57/2016, of August 29, changed by Law 57/2017, of July 19.