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The nature of the charge-ordered state in $Y_{0.5}Ca_{0.5}MnO_3$ with a very small average radius of the A-site cations

Arulraj, Anthony and Gundakaram, R and Biswas, Amlan and Gayathri, N and Raychaudhuri, AK and Rao, CNR (1998) The nature of the charge-ordered state in $Y_{0.5}Ca_{0.5}MnO_3$ with a very small average radius of the A-site cations. In: Journal of Physics: Condensed Matter, 10 (20). pp. 4447-4456.

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Abstract

A detailed investigation of $Y_{0.5}Ca_0.5}MnO_3$ with a very small radius of the A-site cations $(\langle r_A \rangle \approx 1.13 \AA)$ reveals the occurrence of a charge- ordering transition in the paramagnetic state, at a relatively high temperature of 260 K. The orthorhombic lattice distortion, as measured by the dimensionless index D, is large $(\sim 1.75%)$ over the entire 300–100 K range, but the antiferromagnetic interactions become prominent only at low temperatures (<160 K). The charge-ordering gap in $Y_{0.5}Ca_{0.5}MnO_3$, measured by low-temperature vacuum tunnelling spectroscopy, is large $(\sim0.5 eV)$ and the charge-ordered state is unaffected by the application of a magnetic field of 6 T. The study indicates that the nature of charge-ordering in $Y_{0.5}Ca_{0.5}MnO_3$ which is dominated by the cooperative Jahn–Teller effect and the associated lattice distortion is distinctly different from analogous manganates with larger $\langle r_A \rangle$.

Item Type: Journal Article
Additional Information: Copyright of this article belongs to IOP.
Department/Centre: Division of Chemical Sciences > Solid State & Structural Chemistry Unit
Division of Physical & Mathematical Sciences > Physics
Date Deposited: 08 Jan 2007
Last Modified: 19 Sep 2010 04:33
URI: http://eprints.iisc.ernet.in/id/eprint/9368

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