Influence of pH on the structural optical and magnetic properties of Zn1-xMnxO thin films grown by sol-gel method


Goktas A., Mutlu İ. H., Yamada Y., ÇELİK E.

Journal of Alloys and Compounds, vol.553, pp.259-266, 2013 (SCI-Expanded) identifier

  • Publication Type: Article / Article
  • Volume: 553
  • Publication Date: 2013
  • Doi Number: 10.1016/j.jallcom.2012.11.097
  • Journal Name: Journal of Alloys and Compounds
  • Journal Indexes: Science Citation Index Expanded (SCI-EXPANDED), Scopus
  • Page Numbers: pp.259-266
  • Keywords: Ferromagnetic/ paramagnetic responses, pH effect, Room temperature ferromagnetism, Sol-gel process, Zn1-xMnxO thin films
  • Akdeniz University Affiliated: No

Abstract

In this research, Zn1-xMnxO (0 ≤ x ≤ 0.2) thin films were synthesized by sol-gel technique for ferromagnetic and paramagnetic responses at high and low temperatures. In this respect, the produced films were characterized through X-ray diffraction (XRD), scanning electron microscope (SEM), UV-vis spectrometer and superconducting quantum interference device (SQUID) magnetometer. Based on the characterizations and measurements, the influence of pH on the structural, optical and magnetic properties of a Zn1-xMnxO thin films was scrutinized in detail. The analyzed results indicate that the films possess a good crystal quality and homogeneous, smooth surfaces with a pure hexagonal zincsite syn structure of ZnO without any Mn based phases. By increasing the Mn content, the films exhibited increase or decrease in both the c-axis lattice constant and fundamental band gap energy depending on their respective pH. It is clear that the Zn1-xMnxO (x = 0.02 and 0.05) thin films prepared at pH of 4.6 exhibited both a ferromagnetic at high temperatures (100, 200, and 300 K) and a paramagnetic response at low temperature (5 K), whilst Zn1-xMnxO (0.01 ≤ x ≤ 0.2) films prepared at pH value of 7.56 have paramagnetic behavior and antiferromagnetic contributions. The observed room temperature ferromagnetic behavior of the Zn1-xMnxO (x = 0.02 and 0.05) thin films at pH of 4.6 may be related to the interaction between Mn doping and the oxygen vacancies, an oxygen-vacancy-stabilized metastable phase Mn 2-xZnxO3-d or clustering of Mn ions. © 2012 Elsevier B.V. All rights reserved.