Temperature dependence of the gap in the density of states near the Fermi level in a hole doped manganite

Kar, Sohini and Mitra, J and Raychaudhuri, AK (2005) Temperature dependence of the gap in the density of states near the Fermi level in a hole doped manganite. In: Solid State Communications, 136 (7). pp. 410-415.

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Abstract

In this paper, we report a model-based quantitative analysis of temperature dependent scanning tunneling spectroscopy (STS) data taken on epitaxial thin films of the hole doped manganite $La_{0.7}Ca_{0.3}MnO_{3}$. The film, grown on lattice matched $NdGaO_{3}$ substrate, has a ferromagnetic transition temperature $T_{c}$ = 268 K. The analysis allows us to evaluate how the tunneling curve evolves across the transition temperature. We find that there is a gap Delta the density of states (DOS), which peaks at T approximate to $T_{c}$. The gap closes in the ferromagnetic state following the evolution of the magnetization. The gap closing is gradual and not sudden at T = $T_{c}$. Above $T_{c}$ the gap reduces from the peak value and reaches a limiting value of approximate to 75 meV for T/$T_{c}$ \geq 1.1 which is close to the value of 60 meV seen from transport experiments.

Item Type:	Journal Article
Publication:	Solid State Communications
Publisher:	Elsevier Science Ltd
Additional Information:	Copyright for this article belongs to Elsevier.
Keywords:	A. Manganites;C. Scanning tunneling microscopy;D. tunneling
Department/Centre:	Division of Physical & Mathematical Sciences > Physics
Date Deposited:	14 Dec 2005
Last Modified:	19 Sep 2010 04:22
URI:	http://eprints.iisc.ac.in/id/eprint/4650

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