Exploring weak ferromagnetism and conduction mechanism in the layered oxide BiPbSr 2 MnO 6

  • PDF / 2,512,357 Bytes
  • 9 Pages / 595.276 x 790.866 pts Page_size
  • 19 Downloads / 163 Views

DOWNLOAD

REPORT


Exploring weak ferromagnetism and conduction mechanism in the layered oxide BiPbSr2MnO6 S. R. Mohapatra1,2,*, B. Sahu2, S. D. Kaushik3, Gurudayal Behera4, and A. K. Singh2,*

1

Department of Physics & Mathematics, Faculty of Science, Sri Sri University, Cuttack, Odisha 754006, India Department of Physics and Astronomy, National Institute of Technology Rourkela, Rourkela, Odisha 769008, India 3 UGC-DAE-Consortium for Scientific Research Mumbai Centre, R-5 Shed, BARC, Mumbai 400085, India 4 Department of Energy Science & Engineering, Indian Institute of Technology Bombay, Mumbai 400076, India 2

Received: 6 August 2020

ABSTRACT

Accepted: 9 November 2020

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 lowfrequency and high-frequency relaxation have activation energy 0.35 eV and 0.48 eV, respectively.

Ó

Springer Science+Business

Media, LLC, part of Springer Nature 2020

1 Introduction In the past few decades, with the advent of layered Bi-based cuprates having general formula Bi2Sr2Can-1CunO6?2n?d, it has gathered enormous attention for its strong structural modulations, higher superconducting transition temperature and the

possibility to show magnetoelectric (ME) effect [1–4]. It had been proposed that superconductivity originates in cuprates due to CuO2 layers, while the structural modulations originates in Bi-O layers associated with extra oxygen inserted in these layers [2, 5]. The structural modulations in these layered compounds are believed to have a direct influence on

Address correspondence to E-mail: [email protected]; [email protected]

https://doi.org/10.1007/s10854-020-04869-4

J Mater Sci: Mater Electron

magnetic properties of the materials. The structural modulations on magnetism may effectively yield magnetically induced ferroelectricity resulting in ME coupling [6–9]. Soon after, several studies were initiated on related non-superconductive and modulation-free materials by replacing Bi with Pb and part