Room Temperature Ferromagnetism and Band Gap Investigations in Mg Doped ZnO RF/DC Sputtered Films

2013 ◽  
Vol 1494 ◽  
pp. 115-120
Author(s):  
Sreekanth K. Mahadeva ◽  
Zhi-Yong Quan ◽  
J. C. Fan ◽  
Hasan B Albargi ◽  
Gillian A Gehring ◽  
...  
Keyword(s):  
Magnetic Properties ◽  
Saturation Magnetization ◽  
Band Gap ◽  
Room Temperature ◽  
Room Temperature Ferromagnetism ◽  
Band Gap Energy ◽  
Thickness Variation ◽  
Zno Films ◽  
Ambient Conditions ◽  
Partial Pressures

ABSTRACTMg@ZnO thin films were prepared by DC/RF magnetron co-sputtering in (N2+O2) ambient conditions using metallic Mg and Zn targets. We present a comprehensive study of the effects of film thickness, variation of O2 content in the working gas and annealing temperature on the structural, optical and magnetic properties. The band gap energy of the films is found to increase from 4.1 to 4.24 eV with the increase of O2 partial pressures from 5 to 20 % in the working gas. The films are found to be ferromagnetic at room temperature and the saturation magnetization increases initially with the film’s thickness reaching a maximum value of 14.6 emu/cm3 and then decreases to finally become diamagnetic beyond 95 nm thickness. Intrinsic strain seems to play an important role in the observed structural and magnetic properties of the Mg@ZnO films. On annealing, the as-obtained ‘mostly amorphous’ films in the temperature range 600 to 800°C become more crystalline and consequently the saturation magnetization values reduce.

Room Temperature Ferromagnetism and Band Gap Engineering in Mg Doped ZnO RF/DC Sputtered Films

2013 ◽  
Vol 1577 ◽  
Author(s):  
Sreekanth K. Mahadeva ◽  
Zhi-Yong Quan ◽  
Jin-Cheng Fan ◽  
Hasan B. Albargi ◽  
Gillian A Gehring ◽  
...  
Keyword(s):  
Band Gap ◽  
Room Temperature ◽  
Room Temperature Ferromagnetism ◽  
Ambient Conditions ◽  
Zno Film ◽  
Band Gap Engineering ◽  
Sputtered Films ◽  
Doped Zno ◽  
Mg Doped ◽  
Comprehensive Study

ABSTRACTMg doped ZnO thin films were prepared by DC/RF magnetron co-sputtering in (Ar+O2) ambient conditions using metallic Mg and Zn targets. We present a comprehensive study of the effects of film thickness on the structural, optical and magnetic properties. Room temperature ferromagnetism was observed in the films and the saturation magnetization (MS) increases at first as the film’s thickness increases and then decreases. The MS value as high as ∼15.76 emu/cm3 was achieved for the Mg-doped ZnO film of thickness 120 nm. The optical band gap of the films determined to be in the range 3.42 to 3.52 eV.

Robust room temperature ferromagnetism and band gap tuning in nonmagnetic Mg doped ZnO films

2017 ◽  
Vol 399 ◽  
pp. 751-757 ◽  
Author(s):  
Zhiyong Quan ◽  
Xia Liu ◽  
Yan Qi ◽  
Zhilin Song ◽  
Shifei Qi ◽  
...  
Keyword(s):  
Band Gap ◽  
Room Temperature ◽  
Room Temperature Ferromagnetism ◽  
Zno Films ◽  
Doped Zno ◽  
Band Gap Tuning ◽  
Mg Doped

The effect of Oxygen partial pressure during deposition in the magnetic properties of ZnO thin film

2011 ◽  
Vol 1292 ◽  
Author(s):  
Anis Biswas ◽  
Wang Shirong ◽  
Sandeep Nagar ◽  
L. Belova ◽  
K. V. Rao
Keyword(s):  
Magnetic Properties ◽  
Total Pressure ◽  
Room Temperature ◽  
Room Temperature Ferromagnetism ◽  
Zno Thin Films ◽  
Zno Thin Film ◽  
Xrd Study ◽  
Maximum Value ◽  
Partial Pressures ◽  
Effect Of Oxygen

ABSTRACTWe have studied the magnetic properties of 100 nm thick ZnO thin films prepared by magnetron sputtering in different oxygen partial pressures (ratio of oxygen pressure to total pressure in deposition chamber, POxy). Only the films fabricated at POxy below ~ 0.5 show room temperature ferromagnetism. The saturation magnetization at room temperature is initially found to increase as POxy increases and reaches maximum value of ~ 5 emu/gm at POxy ~ 0.3 and then starts to decrease and becomes diamagnetic for POxy > 0.5. From small angle XRD study of structural properties of the films, we find that the lattice stress developed in the film along c-axis also exhibits a similar behavior with the variation of POxy. Thus, both the room temperature ferromagnetism and lattice stress appear to originate from the intrinsic defects present in the sample.

scholarly journals Improving the Room-Temperature Ferromagnetism in ZnO and Low-Doped ZnO:Ag Films Using GLAD Sputtering

Materials ◽  
2021 ◽  
Vol 14 (18) ◽  
pp. 5337
Author(s):  
Marcio A. Correa ◽  
Armando Ferreira ◽  
Raphael M. Tromer ◽  
Leonardo D. Machado ◽  
Matheus Gamino ◽  
...  
Keyword(s):  
Magnetic Properties ◽  
Room Temperature ◽  
Room Temperature Ferromagnetism ◽  
Ferromagnetic Metal ◽  
Zno Films ◽  
Ferromagnetic Behavior ◽  
Sensor Element ◽  
Promising Candidate ◽  
Doped Zno ◽  
Metal Doped

ZnO and doped ZnO films with non-ferromagnetic metal have been widely used as biosensor elements. In these studies, the electrochemical measurements are explored, though the electrical impedance of the system. In this sense, the ferromagnetic properties of the material can be used for multifunctionalization of the sensor element using external magnetic fields during the measurements. Within this context, we investigate the room-temperature ferromagnetism in pure ZnO and Ag-doped ZnO films presenting zigzag-like columnar geometry. Specifically, we focus on the films’ structural and quasi-static magnetic properties and disclose that they evolve with the doping of low-Ag concentrations and the columnar geometry employed during the deposition. The magnetic characterization reveals ferromagnetic behavior at room temperature for all studied samples, including the pure ZnO one. By considering computational simulations, we address the origin of ferromagnetism in ZnO and Ag-doped ZnO and interpret our results in terms of the Zn vacancy dynamics, its substitution by an Ag atom in the site, and the influence of the columnar geometry on the magnetic properties of the films. Our findings bring to light an exciting way to induce/explore the room-temperature ferromagnetism of a non-ferromagnetic metal-doped semiconductor as a promising candidate for biosensor applications.

Annealing Effects on Structural and Magnetic Properties of Al doped ZnO Thin Films

2011 ◽  
Vol 239-242 ◽  
pp. 2835-2838
Author(s):  
Yun Kai Qi ◽  
Jian Jun Gu ◽  
Li Hu Liu ◽  
Hui Yuan Sun
Keyword(s):  
Magnetic Properties ◽  
Room Temperature ◽  
Room Temperature Ferromagnetism ◽  
Zno Films ◽  
Annealing Atmosphere ◽  
X Ray Diffraction ◽  
Annealing Effects ◽  
Order Of Magnitude ◽  
Doped Zno ◽  
A Charge

Al doped ZnO films have been prepared by dc magnetron sputtering. These films were annealed in different atmosphere and temperature. The crystal structures were analyzed by x-ray diffraction (XRD), and the magnetic properties were measured by a Physical Properties Measurement System (PPMS) with the magnetic field paralleled to the films plane. The results show the microstructure and magnetic properties were influenced by annealing atmosphere. Compared to the films annealed in vacuum, the films annealed in air shows obvious room temperature ferromagnetism, the magnetic moment increases about an order of magnitude. The room temperature ferromagnetism may be associated with a charge transfer between Al and Zn and the variational position of Al in ZnO films in different annealing ambience.

Room Temperature Ferromagnetism in Al-doped/Al2O3-doped ZnO Film

2009 ◽  
Vol 1201 ◽  
Author(s):  
Yuwei Ma ◽  
Jun Ding ◽  
Min Ran ◽  
Xue Lian Huang ◽  
Chee Mang Ng
Keyword(s):  
Magnetic Property ◽  
Charge Transfer ◽  
Saturation Magnetization ◽  
Amorphous Phase ◽  
Room Temperature ◽  
Room Temperature Ferromagnetism ◽  
Zno Films ◽  
Zno Film ◽  
Zno Nanocrystals ◽  
Doped Zno

AbstractIn this manuscript, we study the magnetic property of Al-doped/Al2O3-doped ZnO films. We found that metallic Al-doped ZnO film shows room temperature ferromagnetism (RTFM). RTFM is correlated with the interaction of Al metallic clusters and ZnO matrix. The charge transfer has been observed between metallic Al and ZnO matrix. Therefore, RTFM in metallic Al doped ZnO may be highly probable due to charge transfer between metallic Al clusters and ZnO matrix. For Al2O3-doped ZnO film (denoted as (Zn1-x, Alx)O), RTFM was found in (Zn1-x, Alx)O film with a certain Al concentration range (16 mol%<x<50 mol%). The saturation magnetization is maximized in (Zn0.70, Al0.30)O film. The mechanism of RTFM can be explained as the interaction of ZnO nanocrystals (NCs) embedded in the amorphous phase and defects surrounding them.

The Structure and Magnetic Properties of NiZn-Ferrite Films Deposited by Magnetron Sputtering at Room Temperature

2013 ◽  
Vol 690-693 ◽  
pp. 1702-1706 ◽  
Author(s):  
Shuang Jun Nie ◽  
Hao Geng ◽  
Jun Bao Wang ◽  
Lai Sen Wang ◽  
Zhen Wei Wang ◽  
...  
Keyword(s):  
Thin Films ◽  
Magnetic Properties ◽  
Magnetron Sputtering ◽  
Saturation Magnetization ◽  
Room Temperature ◽  
Oxygen Flow ◽  
Flow Ratio ◽  
Study Results ◽  
Ferrite Thin Films ◽  
Ferrite Films

NiZn-ferrite thin films were deposited onto silicon and glass substrates by radio frequency magnetron sputtering at room temperature. The effects of the relative oxygen flow ratio on the structure and magnetic properties of the thin films were investigated. The study results reveal that the films deposited under higher relative oxygen flow ratio show a better crystallinity. Static magnetic measurement results indicated that the saturation magnetization of the films was greatly affected by the crystallinity, grain dimension, and cation distribution in the NiZn-ferrite films. The NiZn-ferrite thin films with a maximum saturation magnetization of 151 emucm-3, which is about 40% of the bulk NiZn ferrite, was obtained under relative oxygen flow ratio of 60%.

Effect of defects on room-temperature ferromagnetism of Cr-doped ZnO films

2009 ◽  
Vol 60 (4) ◽  
pp. 214-217 ◽  
Author(s):  
L.J. Zhuge ◽  
X.M. Wu ◽  
Z.F. Wu ◽  
X.M. Chen ◽  
Y.D. Meng
Keyword(s):  
Room Temperature ◽  
Room Temperature Ferromagnetism ◽  
Zno Films ◽  
Doped Zno

Optical Detection of Band Gap Variations Due to Ordering in Ga0.47In0.53As on InP

1992 ◽  
Vol 281 ◽  
Author(s):  
D. J. Arent ◽  
K. A. Bertness ◽  
Sarah R. Kurtz ◽  
M. Bode ◽  
J. M. Olson
Keyword(s):  
Band Gap ◽  
Atmospheric Pressure ◽  
Room Temperature ◽  
Energy Gap ◽  
Growth Conditions ◽  
Band Gap Energy ◽  
Optical Energy Gap ◽  
Lower Growth ◽  
Transmission Electron ◽  
High Resolution Images

ABSTRACTA reduction in the optical energy gap of more than 65 meV has been observed in In0.53Ga0.47 As grown on (100) InP by atmospheric pressure metalorganic vapor phase epitaxy. The band gap energies were deduced from room temperature photocurrent spectroscopic measurements, accounting for differences in composition and strain. Spontaneous CuPt type ordering of In and Ga atoms on the (111) subplanes of the InGaAs2 was confirmed by transmission electron microscopy. Superlattice signatures in the transmission micrographs were observed only for samples with associated reduced band gap energies, and were confirmed by visible double periodicity in high resolution images. In0.53Ga0.47 As was grown under a variety of conditions, some which promoted ordering. In general, lower growth temperatures and moderate (∼4 μ/hr) growth rates promoted a greater degree of ordering and reduction of the band gap energy. The influence of growth conditions on the ordered structure is considered within the context of current theories.

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