pISSN 0374-4914 eISSN 2289-0041

## Research Paper

New Physics: Sae Mulli 2016; 66: 402-406

Published online April 29, 2016 https://doi.org/10.3938/NPSM.66.402

## Influence of the Deposition Parameters on the Surface Morphology and the Electrical Resistance of CaMnO$_{3}$ and La$_{0.7}$Ca$_{0.3}$MnO$_{3}$ Epitaxial Thin Films

Hien Nguyen VAN, Heon-Jung KIM*

Department of Physics, College of Natural Science, Daegu University, Daegu 42400, Korea

Correspondence to:hjkim76@daegu.ac.kr

Received: December 14, 2015; Revised: January 4, 2016; Accepted: January 4, 2016

This is an open-access article distributed under the terms of the Creative Commons Attribution Non-Commercial License (http://creativecommons.org/licenses/by-nc/3.0/) which permits unrestricted non-commercial use, distribution, and reproduction in any medium, provided the original work is properly cited.

### Abstract

In this study, CaMnO$_{3}$ (CMO) and La$_{0.7}$Ca$_{0.3}$MnO$_{3}$ (LCMO) epitaxial thin films were deposited on (100) SrTiO$_{3}$ (STO) single-crystal substrates from CaMnO$_{3}$ and La$_{0.7}$Ca$_{0.3}$MnO$_{3}$ polycrystalline targets by using pulse laser deposition (PLD) techniques. Among the PLD growth parameters, such as the oxygen partial pressure, substrate temperature, and energy density, we mainly focused on the influence of the energy density. Using high-resolution X-ray diffraction (HRXRD), atomic force microscopy (AFM), and resistivity measurements, we determined the crystallinity, morphology, and electrical properties of the CMO and the LCMO films. While CMO was insulating as expected, the LCMO thin films exhibited the expected metal-insulator transition at 220 K ? 250 K only after oxygen annealing. The surfaces of the LCMO films were smooth and uniform with small grains. On the other hand, the surfaces of the CMO films had characteristic surface textures, which are believed to result from the relatively large strain between the CMO film and the STO substrate. Consistently, HRXRD data on LCMO showed Kiessig fringes while those on CMO did not.

Keywords: Manganites, Epilayers, Heterostructures, Magnetism