Enhancement of ordering temperatures of la0.67Ca 0.33MnO3 thin films by adding Ho atoms
Journal
Physica Status Solidi (B) Basic Research
Journal Volume
244
Journal Issue
12
Pages
4558-4561
Date Issued
2007
Author(s)
Abstract
Abstract A series of Ho x ‐La 0.67 Ca 0.33 MnO 3 thin films with x = 0.0, 0.2, 04, 0.6, and 1.0 mol percent have been deposited on SrTiO 3 (100) substrates with the substrate temperature controlled at 600 o C by dc magnetron sputtering. The magnetic ordering ( T c ) and metal‐insulator transition temperature ( T MI ) were enhanced about 25∼60 K for Ho x ‐La 0.67 Ca 0.33 MnO 3 films. At x = 0.4 the ordering temperature has been increased above 280 K. The variation of the ordering temperature is simply ascribed to the presence of Ho. The results of magnetoresistance measurements indicated that the samples exhibited colossal magnetoresistance effect (CMR) and a maximum was observed at a temperature T P . It was noted that the variation of T P with x displayed the same trend as that of T MI . Although the CMR was suppressed with the addition of Ho, a sizeable CMR ≈ 20% was still detected at 270 K in the sample with 0.4 mol% Ho due to much higher T P . (© 2007 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Type
journal article