Magnetic properties of Mn doped ZnO tetrapod structures

Abstract

ZnO tetrapod nanostructures were prepared by evaporating Zn metal under humid argon flow. After the fabrication, Mn diffusion doping was performed at two different temperatures ͑600 and 800°C͒. The samples were characterized by scanning electron microscopy, transmission electron microscopy, x-ray fluorescence, x-ray diffraction ͑XRD͒, superconducting quantum interference device magnetometer, and photoluminescence. Diffusion doping resulted in the increase of the size of tetrapods, but no new peaks were found in XRD spectrum. Mn doped ZnO tetrapod structures were found to be ferromagnetic with Curie temperature ϳ50 K, and showed large coercive field ͑ϳ3500 Oe for 800°C sample, ϳ5500 Oe for 600°C sample͒.

Nanocrystalline Mn and Fe Doped ZnO Thin Films Prepared Using SILAR Method for Dilute Magnetic Semiconductor Application

“…Such preferred basal orientation is typically observed also in metal doped ZnO films , a, b) (Chandramohan et al, 2010). Moreover, from the recorded spectrums the minor diffraction peaks of (102) and (103) are approved of randomly oriented of the ZnO film (Roy, at al., 2004). The crystallite size was estimated to be 80 nm for undoped film, 26 nm for MZO and 20 nm for FZO films from the Debye Scherrer formula.…”

High-temperature ferromagnetism in pulsed-laser deposited epitaxial (Zn,Mn)O thin films: Effects of substrate temperature

“…There are several reports [7][8][9] where ferromagnetism in bulk, nanostructures and Mn ion-implanted ZnO films has been observed. The reported ferromagnetic transition temperature, however, varies from 50 to 300 K. On the other hand, ZnMnO films prepared by magnetron sputtering, 10 pulsed-laser deposition 11 ͑PLD͒, and polycrystalline samples 12 did not show ferromagnetic behavior.…”

Hydrothermal Synthesis and Properties of Diluted Magnetic Semiconductor Zn<sub>1-x</sub>Mn<sub>x</sub>O Nanowires

“…Figure 5 shows the temperature dependence of the magnetization (M-T) during cooling in a magnetic field of 5 T, the magnetization shows a slight increase from 100 to 40 K, followed by a steep increase below 30 K until 5 K. It can be seen that the FC curve shows a sharp increase at low temperature, this behavior has been considered as the effect of randomness and disorder on percolating FM clusters in most diluted magnetic semiconductor materials. So the Curie temperature of Zn 1-x Mn x O nanowires is about 30 K, which is higher than 25 K and lower than 50 K, observed for ZnMnO thin film and Mn doped ZnO nanotetrapods, respectively [28,29]. It seems that data reported so far on Mn doped ZnO are not quite consistent.…”

“…Therefore, more detailed works are essential to understand the behavior of these materials. Mn doped ZnO nanowires (or nanobelts) have been obtained by doping Mn into ZnO by using various techniques, such as ion implantation [19], thermal evaporation [20][21][22][23]. These methods generally require high temperature and expensive equipments.…”