Manganese-Doped CdGeAs2, ZnGeAs2 and ZnSiAs2 Chalcopyrites: A New Advanced Materials for Spintronics

2010 ◽  
Vol 168-169 ◽  
pp. 31-34 ◽  
Author(s):  
A.S. Morozov ◽  
L.A. Koroleva ◽  
D.M. Zashchirinskii ◽  
T.M. Khapaeva ◽  
S.F. Marenkin ◽  
...  
Keyword(s):  
Room Temperature ◽  
Magnetic Semiconductors ◽  
Dilute Magnetic Semiconductors ◽  
Charge Carriers ◽  
Advanced Materials ◽  
Temperature Dependences ◽  
P Type ◽  
Mn Doped ◽  
Curie Temperatures ◽  
Exchange And Superexchange Interactions

Based on the Mn-doped chalcopyrites CdGeAs2, ZnGeAs2 and ZnSiAs2, new dilute magnetic semiconductors with the p-type conductivity were produced. Magnetization, electrical resistivity and Hall effect of these compositions were studied. Their temperature dependences of magnetization are similar in form in spite of a complicated character, which is controlled by the concentration and mobility of the charge carriers. Thus, for T < 15 K, these curves are characteristic of superparamagnets and for T > 15 K, of a frustrated ferromagnet. In compounds with Zn these two states are diluted by a spinglass-like state. This specific feature is ascribed to attraction of Mn ions occupying neighboring sites and to competition between the carrier-mediated exchange and superexchange interactions. The Curie temperatures of these compounds are above room temperature. These are the highest Curie temperatures in the AIIBIVCV2:Mn systems.

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 Increased room temperature ferromagnetism in Co-doped tetrahedral perovskite niobates

2021 ◽  
Vol 8 (10) ◽  
Author(s):  
Yi Zhou ◽  
Qing He ◽  
Fei Zhou ◽  
Xingqi Liao ◽  
Yong Liu ◽  
...  
Keyword(s):  
Room Temperature ◽  
Magnetic Semiconductors ◽  
Room Temperature Ferromagnetism ◽  
Dilute Magnetic Semiconductors ◽  
Defect Band ◽  
Co Doping ◽  
Band Absorption ◽  
Local Spin Polarization ◽  
Curie Temperatures ◽  
Co Doped

Dilute magnetic semiconductors (DMSs), such as (In, Mn)As and (Ga, Mn)As prototypes, are limited to III–V semiconductors with Curie temperatures ( T c ) far from room temperature, thereby hindering their wide application. Here, one kind of DMS based on perovskite niobates is reported. BaM x Nb (1− x ) O 3− δ ( M = Fe, Co) powders are prepared by the composite-hydroxide-mediated method. The addition of M elements endows BaM x Nb (1− x ) O 3− δ with local ferromagnetism. The tetragonal BaCo x Nb (1− x ) O 3− δ nanocrystals can be obtained by Co doping, which shows strong saturation magnetization ( M sat ) of 2.22 emu g −1 , a remnant magnetization ( M r ) of 0.084 emu g −1 and a small coercive field ( H c ) of 167.02 Oe at room temperature. The ab initio calculations indicate that Co doping could lead to a 64% local spin polarization at the Fermi level ( E F ) with net spin DOS of 0.89 electrons eV −1 , this result shows the possibility of maintaining strong ferromagnetism at room temperature. In addition, the trade-off effect between the defect band absorption and ferromagnetic properties of BaM x Nb (1− x ) O 3− δ is verified experimentally and theoretically.

Room temperature ferromagnetism in III–V and II–IV–V2 dilute magnetic semiconductors

2006 ◽  
Vol 374-375 ◽  
pp. 430-432 ◽  
Author(s):  
V.G. Storchak ◽  
D.G. Eshchenko ◽  
H. Luetkens ◽  
E. Morenzoni ◽  
R.L. Lichti ◽  
...  
Keyword(s):  
Room Temperature ◽  
Magnetic Semiconductors ◽  
Room Temperature Ferromagnetism ◽  
Dilute Magnetic Semiconductors

scholarly journals Synthesis and Characterization of Sodium Bis(2-ethylhexyl) Sulfonsuccinate (AOT) Capped Pure and Mn-Doped CdS Nanoparticles

2012 ◽  
Vol 2012 ◽  
pp. 1-8 ◽  
Author(s):  
D. Venkatesan ◽  
D. Deepan ◽  
J. Ramkumar ◽  
S. Moorthy Babu ◽  
R. Dhanasekaran
Keyword(s):  
Thin Films ◽  
Magnetic Semiconductors ◽  
Dilute Magnetic Semiconductors ◽  
Transition Metal Ions ◽  
Hexagonal Structure ◽  
Cds Nanoparticles ◽  
Sem Images ◽  
Semiconducting Properties ◽  
Mn Doped

CdS nanoparticles and thin films are well known for their excellent semiconducting properties. When transition metal ions are doped into the CdS, it exhibits magnetic properties in addition to semiconducting properties and they are termed as dilute magnetic semiconductors (DMSs). In this paper, we discuss the preparation of sodium bis(2-ethylhexyl) sulfonsuccinate (AOT) capped CdS nanoparticles and thin films doped with magnetic impurity Mn. Sodium bis(2-ethulexyl) sulfonsuccinate (AOT), capping agent promotes the uniform formation of nanoparticles. Optical characterizations are made using the UV-Vis spectrometer, PL, and FTIR. XRD shows the hexagonal structure of the CdS. SEM images and EDS measurements were made for the thin films. EPR shows the clear hyperfine lines corresponding to Mn2+ion in the CdS nanoparticles.

Amorphous magnetic semiconductors with Curie temperatures above room temperature

2019 ◽  
Vol 40 (8) ◽  
pp. 081510 ◽  
Author(s):  
Na Chen ◽  
Kaixuan Fang ◽  
Hongxia Zhang ◽  
Yingqi Zhang ◽  
Wenjian Liu ◽  
...  
Keyword(s):  
Room Temperature ◽  
Magnetic Semiconductors ◽  
Curie Temperatures

Structural, Optical, and Magnetic Behavior of in-situ Doped, MOCVD-Grown Ga1-xMnxN Epilayers and Heterostructures

2005 ◽  
Vol 892 ◽  
Author(s):  
Nola Li ◽  
William E. Fenwick ◽  
Martin Strassburg ◽  
Ali Asghar ◽  
Shalini Gupta ◽  
...  
Keyword(s):  
Raman Spectroscopy ◽  
Active Layer ◽  
Room Temperature ◽  
Vacancy Concentration ◽  
Dilute Magnetic Semiconductors ◽  
Magnetic Behavior ◽  
Nitrogen Vacancy ◽  
Material System ◽  
Mn Concentration ◽  
Mn Doped

AbstractDilute magnetic semiconductors (DMS) show promise as materials that can exhibit ferromagnetism at room temperature (RT). However, the nature of ferromagnetism in this material system must be well understood in order to allow intelligent design of RT spintronic devices. This work investigates the magnetic properties of the as-grown films and the effect of Mn incorporation on crystal integrity and device performance. Ga1-xMnxN films were grown by MOCVD on c-plane sapphire substrates with varying thickness and Mn concentration. Homogenous Mn incorporation throughout the films was verified with Secondary Ion MassSpectroscopy (SIMS), and no macroscopic second phases (MnxNy) were detected using X-ray diffraction (XRD). Superior crystalline quality in the MOCVD-grown films relative to Mn-implanted GaN epilayers was confirmed via Raman spectroscopy. Vibrating sample magnetometry measurements showed an apparent room temperature ferromagnetic hysteresis in the as-grown epiayers. Similarly, a marked decrease in the magnetization was observed with annealing and silicon doping, as well as in post-growth annealed Mg-codoped samples. The observed decrease in muB per Mn with increasing Mn concentration is explained by Raman spectroscopy results, which show a decrease in long-range lattice ordering and an increase in nitrogen vacancy concentration with increasing Mn concentration. Magnetic and electron-spin paramagnetic resonance (EPR) data also show that the position of the Fermi level relative to the Mn2+/3+ level is the determining factor in magnetization. Light emitting diodes (LEDs) containing a Mn-doped active region have also been produced. Devices were fabricated with different Mn-doped active layer thicknesses, and I-V characteristics show that the devices become more resistive as thickness of the Mn-doped active layer increases. The magnetic and structural properties observed in this work will be used in conjunction with characteristics and magneto-optical of the Mn-containing devices to discuss the theoretical models of ferromagnetism in Ga1-xMnxN

SnO2 doped with Mn, Fe or Co: Room temperature dilute magnetic semiconductors

2004 ◽  
Vol 95 (11) ◽  
pp. 7390-7392 ◽  
Author(s):  
C. B. Fitzgerald ◽  
M. Venkatesan ◽  
A. P. Douvalis ◽  
S. Huber ◽  
J. M. D. Coey ◽  
...  
Keyword(s):  
Room Temperature ◽  
Magnetic Semiconductors ◽  
Dilute Magnetic Semiconductors

p-type conductivity and donor-acceptor pair emission in Cd1−xFexS dilute magnetic semiconductors

2006 ◽  
Vol 89 (26) ◽  
pp. 262118 ◽  
Author(s):  
X. J. Wu ◽  
D. Z. Shen ◽  
Z. Z. Zhang ◽  
J. Y. Zhang ◽  
K. W. Liu ◽  
...  
Keyword(s):  
Magnetic Semiconductors ◽  
Dilute Magnetic Semiconductors ◽  
Acceptor Pair ◽  
Type Conductivity ◽  
Donor Acceptor ◽  
Donor Acceptor Pair ◽  
P Type
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