Exploring weak ferromagnetism and conduction mechanism in the layered oxide BiPbSr2MnO6.

Mohapatra, S. R.; Sahu, B.; Kaushik, S. D.; Behera, Gurudayal; Singh, A. K.

Layered oxide BiPbSr2MnO6 (BPSMO), isostructural to 10 K Bi-based cuprates, is prepared by employing solid-state route in nitrogen atmosphere. Phase purity of the compound is determined from the room temperature Rietveld refined X-ray diffraction (XRD) data. BPSMO crystallizes in an orthorhombic crystal structure, thereby confirming its space group as 'A2aa'. Presence of weak ferromagnetism in BPSMO below magnetic transition temperature (TN) is validated from isothermal magnetization data accompanied by the Arrott plot at 2.8 K, in contrast to its antiferromagnetic behavior at 290 K. The coexistence of Mn2 and Mn3 is confirmed from X-ray photoelectron spectroscopy study. The conduction mechanism in BPSMO is studied following two different hopping models, i.e., Arrhenius model for T > 250 K and Mott's variable range hopping (MVRH) model for T < 250 K. The relaxation in BPSMO is found to be polaronic in nature and may have originated due to the mixed valence structure of the sample. Lastly, the frequency domain analysis of dielectric spectra reveals the presence of two distinct relaxations. Moreover, it is determined that the low-frequency and high-frequency relaxation have activation energy 0.35 eV and 0.48 eV, respectively.

FERROMAGNETISM; FREQUENCY-domain analysis; X-ray photoelectron spectroscopy; TRANSITION temperature; MAGNETIC transitions; TRANSITION metal oxides

Journal of Materials Science: Materials in Electronics, 2021, Vol 32, Issue 1, p923

0957-4522

Academic Journal

10.1007/s10854-020-04869-4