Citation
Navasery, Manizheh and Shaari, Abdul Halim and Dehzangi, Arash and Soltani, Nayereh and Bahmanrokh, Ghazaleh and Haghiri, Maryam Erfani and Kamalianfar, Ahmad and Pan, Kai Yap and Chang, Sen Choung and Chen, Soo Kien and Lim, Kean Pah and Awang Kechik, Mohd Mustafa
(2014)
Electrical properties and conduction mechanisms in La2/3Ca1/3MnO3 thin films prepared by pulsed laser deposition on different substrates.
Applied Physics A: Materials Science & Processing, 116 (4).
pp. 1661-1668.
ISSN 0947-8396; ESSN: 1432-0630
Abstract
Perovskite manganite La2/3Ca1/3MnO3 thin films were directly grown on MgO(100), Si(100) and glass substrates by pulsed laser deposition. From the XRD patterns, the films are found to be polycrystalline, single-phase orthorhombic. The metal-insulator transition temperature is 209 K for LCMO/MgO, 266 K for LCMO/Si and 231 K for film deposited on the glass substrate. The conduction mechanism in these films is investigated in different temperature regimes. Low-temperature resistivity data below the phase transition temperature (T P) have been fitted with the relation ρ = ρ0 + ρ 2T2 + ρ 4.5T4.5, indicating that the electron-electron scattering affects the conduction of these materials. The high-temperature resistivity data (T > T P) were explained using variable-range hopping (VRH) and small-polaron hopping (SPH) models. Debye temperature values are 548 K for LCMO/Cg, 568 K for LCMO/Si and 508 K for LCMO/MgO thin films. In all thin films, the best fitting in the range of VRH is found for 3D dimension. The density of states near the Fermi level N (E F) for LCMO/MgO is lower due to the prominent role of the grain boundary in LCMO/MgO and increase in bending of Mn-O-Mn bond angle, which decreases the double exchange coupling of Mn 3+-O2-Mn4+ and in turn makes the LCMO/MgO sample less conducting as compared to the other films.
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