Morphological, electrical and dielectric properties of La_0.6Ga_0.4Fe_1-xMn_xO₃ ceramics

ABSTRACT

Morphological, electrical and dielectric properties of manganese-doped lanthanide orthoferrites La_0.6Ga_0.4Fe_1-xMn_xO₃ (x = 0; 0.1; 0.2 and 0.3) are investigated. Scanning electron microscopy characterization shows that the increase of Mn content increases the rate of the agglomeration and leads to grains with irregular shape. The grain size is estimated and compared with those obtained from X-ray diffraction result. Electrical measurements show that the resistivity decreases with Mn concentration over more than three decades. Also, it is found that dielectric properties are strongly temperature and frequency dependent. The dielectric constant reaches a high value at low frequency. Then, it decreases due to the polarization reduction. The dielectric transition peak appears at the same temperature for different frequencies for the undoped sample La_0.6Ga_0.4FeO_3, while for the doped ones, the peak shifts to the higher temperatures as the frequency increases. Also, dielectric loss decreases with the frequency and a dispersion phenomenon appears.

KEYWORDS:

• Orthoferrites
• scanning electron microscopy
• dielectric properties
• polarization

Acknowledgements

This work has been supported by the Tunisian Ministry of Higher Education and Scientific Research through the funding attributed to LaPhyMNE and URMAN.

Disclosure statement

No potential conflict of interest was reported by the author(s).

Additional information

Funding

This work has been supported by the Tunisian Ministry of Higher Education and Scientific Research through the funding attributed to LaPhyMNE and URMAN.