Effect of Low Temperature Annealing on High Field Magnetoresistance and Hall effect in (Ga, Mn)As Dilute Magnetic Semiconductors

2004 ◽  
Vol 831 ◽  
Author(s):  
K. Ghosh ◽  
Mohammad Arif ◽  
T. Kehl ◽  
R. J. Patel ◽  
S. R. Mishra ◽  
...  
Keyword(s):  
Transition Temperature ◽  
Low Temperature ◽  
High Field ◽  
Magnetic Semiconductors ◽  
Magnetic Semiconductor ◽  
Dilute Magnetic Semiconductors ◽  
Epitaxial Thin Films ◽  
Ferromagnetic Transition ◽  
Optimal Temperature ◽  
Low Temperature Annealing

ABSTRACTIn this paper we report the effect of low temperature annealing on the high field magnetotransport properties of epitaxial thin films of (Ga, Mn)As Dilute Magnetic Semiconductor (DMS) with low concentration (1.5 %) of Mn doping, which results in a ferromagnetic insulator. Annealing at an optimal temperature enhances the conductivity, carrier concentration, and ferromagnetic transition temperature. The field dependence of magnetoresistance is different below and above the ferromagnetic transition temperature. An attempt is made to analyze the data using a theoretical model proposed by Kaminski and Das Sarma [1].

EFFECTS OF PHOTO-EXCITATION AND MAGNON SCATTERING ON FERROMAGNETIC TRANSITION TEMPERATURE OF THE DILUTED MAGNETIC SEMICONDUCTOR (Ga1 - x, Mnx)As

2011 ◽  
Vol 25 (04) ◽  
pp. 273-280 ◽  
Author(s):  
CHERNET AMENTE ◽  
P. SINGH
Keyword(s):  
Transition Temperature ◽  
Spin Wave ◽  
Wave Scattering ◽  
Diluted Magnetic Semiconductor ◽  
Magnetic Semiconductor ◽  
Ferromagnetic Transition ◽  
Photon Irradiation ◽  
Model Hamiltonian ◽  
Diluted Magnetic ◽  
System Properties

Effects of photo-excitation and spin-wave scattering on magnetization of the diluted magnetic semiconductor (DMS) ( Ga , Mn ) As are theoretically studied. Green function formalism is used to find expression for magnetization and ferromagnetic transition temperature TC starting with a model Hamiltonian consisting of magnons, photons and an interaction of magnons with photons. According to our calculation, there is TC in the absence of magnetic impurity, x = 0, indicating that there could be electronically unpaired influential carriers/holes induced by photon irradiation resulting in residual itinerant band magnetization which can be revealed by experiments. Unusual upturn in magnetization near 0 K temperature values for larger magnon–photon coupling constant is also indicated. Moreover, enhancement of magnetization is established with increase in impurity concentration and even further in the presence of photon–magnon coupling which however decreases due to spin-wave scattering. This leads to the conclusion that at lower temperatures photon irradiation and at higher temperatures spin-wave scattering could affect the system properties predominantly.

Magnetization Study of Fe-Based II-VI Diluted Magnetic Semiconductors

1989 ◽  
Vol 161 ◽  
Author(s):  
W.J.M. De Jonge ◽  
H.J.M. Swagten ◽  
A. Twardowski
Keyword(s):  
Low Temperature ◽  
Exchange Interaction ◽  
High Field ◽  
Diluted Magnetic Semiconductors ◽  
Magnetic Semiconductors ◽  
Critical Value ◽  
Nearest Neighbour ◽  
Magnetization Study ◽  
High Field Magnetization ◽  
Diluted Magnetic

ABSTRACTThe high field magnetization for Fe based Diluted Magnetic Semiconductors has been calculated. It is shown that the low temperature magnetization displays characteristic steps, related to the nearest neighbour exchange interaction JNN, provided that JNN exceeds a critical value.

Enhanced ferromagnetic transition temperature in NdOxDy epitaxial thin films

2019 ◽  
Vol 3 (4) ◽  
Author(s):  
Dai Kutsuzawa ◽  
Yasushi Hirose ◽  
Yuki Sugisawa ◽  
Junichi Kikuda ◽  
Daiichiro Sekiba ◽  
...  
Keyword(s):  
Thin Films ◽  
Transition Temperature ◽  
Epitaxial Thin Films ◽  
Ferromagnetic Transition

Effects of clustering and dimensionality on the magnetic properties of diluted magnetic semiconductors

2003 ◽  
Vol 794 ◽  
Author(s):  
R. N. Bhatt ◽  
Malcolm. P. Kennett ◽  
Adel Kassaian
Keyword(s):  
Magnetic Properties ◽  
Transition Temperature ◽  
Diluted Magnetic Semiconductors ◽  
Magnetic Semiconductors ◽  
Mean Field ◽  
Impurity Band ◽  
Growth Conditions ◽  
Band Model ◽  
Ferromagnetic Transition ◽  
Diluted Magnetic

ABSTRACTThe magnetic properties of films of diluted magnetic semiconductors (DMS) such as (Ga,Mn)As, as well as bulk grown crystals of similar materials, have been found to be extremely sensitive to growth conditions, both in terms of the ferromagnetic transition temperature, and the details of their magnetization curves. We study an impurity band model for carriers in Mn-doped DMS applicable in the low carrier density regime, and discuss the effects of clustering on the magnetic properties of DMS, using both numerical mean field and Monte Carlo simulations. In addition, we study the effects of dimensionality on the transition temperature and other magnetic behaviour, and compare our results with experimental data.

scholarly journals Electronic Structure and Room Temperature of 2D Dilute Magnetic Semiconductors in Bilayer MoS2-Doped Mn

2020 ◽  
Vol 2020 ◽  
pp. 1-8
Author(s):  
Sintayehu Mekonnen Hailemariam
Keyword(s):  
Electronic Structure ◽  
Room Temperature ◽  
Magnetic Semiconductors ◽  
Magnetic Semiconductor ◽  
Dilute Magnetic Semiconductors ◽  
Magnetic Interaction ◽  
Spatial Distance ◽  
Atomic Distance ◽  
Dilute Limit ◽  
Mn Doped

The electronic structure and magnetic properties of manganese- (Mn-) doped bilayer (BL) molybdenum disulfide (MoS2) are studied using the density function theory (DFT) plus on-site Hubbard potential correction (U). The results show that the substitution of Mn at the Mo sites of BL MoS2 is energetically favorable under sulfur- (S-) rich regime than Mo. The magnetic interaction between the two manganese (Mn) atoms in BL MoS2 is always ferromagnetic (FM) irrespective of the spatial distance between them, but the strength of ferromagnetic interaction decays with atomic distance. It is also found that two dopants in different layers of BL MoS2 communicate ferromagnetically. In addition to this, the detail investigation of BL MoS2 and its counterpart of monolayer indicates that interlayer interaction in BL MoS2 affects the magnetic interaction in Mn-doped BL MoS2. The calculated Curie temperature is 324, 418, and 381 K for impurity concentration of 4%, 6.25%, and 11.11%, respectively, which is greater than room temperature, and the good dilute limit of dopant concentration is 0–6.25%. Based on the finding, it is proposed that Mn-doped BL MoS2 are promising candidates for two-dimensional (2D) dilute magnetic semiconductor (DMS) for high-temperature spintronics applications.

scholarly journals Synthesis, characterization and promising properties of Fe3O4/CdSe nanocomposite

2019 ◽  
Vol 201 ◽  
pp. 02002
Author(s):  
Shaimaa A. Habib ◽  
Mona B. Mohamed ◽  
Samia A. Saafan ◽  
Talaat M. Meaz
Keyword(s):  
Magnetic Properties ◽  
Active Sites ◽  
Magnetic Measurements ◽  
Magnetic Semiconductors ◽  
Magnetic Semiconductor ◽  
Dilute Magnetic Semiconductors ◽  
Spherical Shape ◽  
Optical Measurements ◽  
Precipitation Method ◽  
Semiconductor Nanocomposites

Nowadays there is a continuously increasing worldwide concern for the utilization of magnetic semiconductor nanocomposites. We synthesized bifunctional magnetic–luminescent nanocomposites with Fe3O4 nanoparticles as the cores and CdSe as the shells by a facile direct precipitation method. Transmission electron microscopy (TEM) images revealed that the obtained bifunctional nanocomposites had a core–shell structure, in a spherical shape with a particle radius of about 10.3nm, and the shell thickness of about 2.2nm. The flower shape is due to the inhomogeneous growth of CdSe due to the presence of many active sites which turn to be nucleation centers for the CdSe on the surface of the nano-magnetite. The X-ray diffraction (XRD) patterns showed a cubic spinel structure of the Fe3O4 core. Magnetic measurements indicated that the presence of CdSe in the composite reduces its magnetic properties. Optical measurements of the Fe3O4/CdSe nanocomposite show that the prepared samples have dual functions, optical tunable band gap of the semiconductor quantum dots and the magnetic properties of magnetite. This type of composites would be considered as dilute magnetic semiconductors (DMS).

A Review on Chemical Synthesis, Characterization and Optical Properties of Nanocrystalline Transition Metal Doped Dilute Magnetic Semiconductors

2013 ◽  
Vol 201 ◽  
pp. 103-129 ◽  
Author(s):  
Tokeer Ahmad ◽  
Sarvari Khatoon ◽  
Ruby Phul
Keyword(s):  
Optical Properties ◽  
Transition Metal ◽  
Magnetic Semiconductors ◽  
Room Temperature Ferromagnetism ◽  
Magnetic Semiconductor ◽  
Dilute Magnetic Semiconductors ◽  
Exchange Interactions ◽  
Transition Metal Ions ◽  
Modern Technology ◽  
Metal Doped

Nanomaterials have fascinated researchers in recent years because these materials exhibit unusual optical, magnetic and electrical properties as compared to their bulk counterparts. Incorporating impurity ions into a semiconducting host to extend its properties has been one of the most important techniques that paved the way for the modern technology based on spintronic devices. Over the past few years, oxide based dilute magnetic semiconductors (DMSs) have gained remarkable interest due to the possibility of inducing room temperature ferromagnetism. This review describes the experimental developments and optical properties of oxide based DMSs, including the recent results on ZnO, CdO and In2O3 based systems. Optical properties of transition metal (TM)-doped ZnO, CdO and In2O3 dilute magnetic semiconductor nanoparticles show red shift in energy band gaps. Such types of phenomena are attributed to sp-d exchange interactions between band electrons and localized d-electrons of the substituted transition metal ions. Table of Contents

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