화학공학소재연구정보센터
Materials Research Bulletin, Vol.42, No.6, 1119-1127, 2007
La0.67Ca0.33MnO3 thin films on Si(100) by DC magnetron sputtering technique using nanosized powder compacted target
La0.67Ca0.33MnO3 (LCMO) thin films were successfully fabricated by a DC magnetron sputtering technique on Si (10 0) substrates from chemically synthesized compacted powders. Powders of proper stochiometry composites were synthesized by a novel chemical technique [DR. Sahu, B.K. Roul, P. Pramanik, J.L. Huang, Physica B 369 (2005) 209] and were found to be nanosized (approximate to 40-50 nm). The sinterability of the powders were improved significantly due to their large surface area with a reduction of sintering temperature (up to 500 degrees C) as compared to the powders prepared by other solid-state reaction route. Bulk LCMO targets were prepared and preliminary structural and magnetic properties of target were investigated for colossal magnetoresistance (CMR) properties. Films deposition parameters like DC power, gas flow rate, deposition time, etc., were critically optimized to achieve desired thickness of film using above LCMO target by DC magnetron sputtering. LCMO films fabricated on Si (1 0 0) substrates showed enhanced magnetoresistance (MR) at low temperature. Maximum MR of about 1000% was observed at 100 K. Paramagnetic to ferromagnetic transitions were observed in films below room temperature and were found at approximately 240 K. However, as compared to bulk target prepared by a chemical route, it was found that Curie temperature (T-c) and MR response of bulk target were higher than the thin films. Preliminary point chemical analysis revealed the deficiency of Ca2+ ions in CMR films. (C) 2006 Elsevier Ltd. All fights reserved.