# EPR Study on the Role of Manganese in Enhancing PTC of $BaTiO_3$

Kutty, TRN and Murugaraj, P (1985) EPR Study on the Role of Manganese in Enhancing PTC of $BaTiO_3$. In: Materials Letters, 3 (5-6). pp. 195-199.

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## Abstract

Low concentration of Mn (< 0.05 atom%) added to lanthanide-doped ceramics for enhancing the PTC effect did not show any EPR signal due to Mn in the tetragonal phase. Above $T_c$ (400 K) it showed the six-line signal arising from $Mn^2^+$. This is explained on the basis of Mn existing as $Mn^3^+$ ion with short relaxation time at room temperature. Oxidation state changes to $Mn^2^+$ above $T_c$; thus $Mn^3^+$ acts as an electron trap. This augments the function of activated defect centres $(V_{Ba} \rightleftharpoons V^{\prime}_B_a)$ in diminishing the charge carrier concentration across the phase transformation.

Item Type: Journal Article Copyright of this article belongs to Elsevier. Division of Chemical Sciences > Materials Research Centre 10 Jul 2008 19 Sep 2010 04:47 http://eprints.iisc.ernet.in/id/eprint/14902