Akademik Veri Yönetim Sistemi
Thin Solid Films, cilt.520, sa.19, ss.6138-6144, 2012 (SCI-Expanded)
Manganite La 0.67Ag 0.33MnO 3 (LAgMO) and La 0.67K 0.33MnO 3 (LKMO) films have been obtained on a single-crystal of LaAlO 3 (100) and quartz substrates using sol-gel dip-coating technique. Structural, electrical, magnetic and magnetoresistance properties of the films have been investigated. X-ray diffraction patterns of the films grown on LaAlO 3 (100) substrate showed to be highly oriented in the direction of (100) and the films grown on the quartz substrate have perovskite with rhombohedral structure. The oriented films exhibited typical transport properties, whereas the polycrystalline films showed significantly different behaviors of the temperature dependent resistivity, magnetization and magnetoresistance (MR). The epitaxial films of the LAgMO and LKMO showed different metal-insulator transition temperature (T MI) and the paramagnetic-ferromagnetic phase transition temperature (T C). This was mainly due to the different ionic radius size of Ag 1+ and K 1+. The variation of T MI and T C was due to the different annealing temperatures and grain size effect in the polycrystalline films. The polycrystalline films showed a higher MR than the corresponding epitaxial films. An extrinsic MR has been observed at low temperatures (< 100 K) for the polycrystalline films due to the spin dependent scattering of conduction electrons at grain boundaries. © 2012 Elsevier B.V. All rights reserved.