Depletion of the density of states at the Fermi level in metallic colossal magnetoresistive manganites

Mitra, J and Raychaudhuri, AK and Mukovskii, Ya M and Shulyatev, D (2003) Depletion of the density of states at the Fermi level in metallic colossal magnetoresistive manganites. In: Physical Review B (Condensed Matter and Materials Physics -1(I)), 68 (13). 134428-1-8.

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Abstract

We have performed tunneling spectroscopy measurements down to 4.2 K on single crystals of La0.75Sr0.25MnO3 and La0.7Ca0.3MnO3, which show the colossal magnetoresistive behavior in the ferromagnetic metallic phase. The tunneling spectroscopy measurements give information on the density of states (DOS) at and close to the Fermi level EF. The observed energy dependence of the DOS is similar to that seen in correlated oxides with disorder, which is an important observation since it raises fundamental questions regarding the nature of the metallic state in these oxides. Measurements at low temperatures reveal that the DOS in these compounds show a depletion close to EF, |E–EF|< 15 meV; unlike that in conventional metals. The normalized DOS, close to EF shows an energy dependence alpha |E–EF|2 at low temperatures but remains finite as E - EF. The depth of the depletion is more in La0.7Ca0.3MnO3 compared to La0.75Sr0.25MnO3.

Item Type:	Journal Article
Publication:	Physical Review B (Condensed Matter and Materials Physics -1(I))
Publisher:	American Physical Society
Additional Information:	Copyright for this article belongs to American Physical Society (APS)
Department/Centre:	Division of Physical & Mathematical Sciences > Physics
Date Deposited:	23 Aug 2004
Last Modified:	19 Sep 2010 04:14
URI:	http://eprints.iisc.ac.in/id/eprint/1317

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