scholarly journals Interfacial dominated ferromagnetism in nanograined ZnO: a μSR and DFT study

2015 ◽  
Vol 5 (1) ◽  
Author(s):  
Thomas Tietze ◽  
Patrick Audehm ◽  
Yu–Chun Chen ◽  
Gisela Schütz ◽  
Boris B. Straumal ◽  
...  
Keyword(s):  
Grain Boundaries ◽  
Density Functional ◽  
Room Temperature ◽  
Volume Fraction ◽  
Muon Spin ◽  
Room Temperature Ferromagnetism ◽  
Sample Volume ◽  
Functional Theory ◽  
Spintronic Devices ◽  
Magnetic Ions

Abstract Diamagnetic oxides can, under certain conditions, become ferromagnetic at room temperature and therefore are promising candidates for future material in spintronic devices. Contrary to early predictions, doping ZnO with uniformly distributed magnetic ions is not essential to obtain ferromagnetic samples. Instead, the nanostructure seems to play the key role, as room temperature ferromagnetism was also found in nanograined, undoped ZnO. However, the origin of room temperature ferromagnetism in primarily non–magnetic oxides like ZnO is still unexplained and a controversial subject within the scientific community. Using low energy muon spin relaxation in combination with SQUID and TEM techniques, we demonstrate that the magnetic volume fraction is strongly related to the sample volume fraction occupied by grain boundaries. With molecular dynamics and density functional theory we find ferromagnetic coupled electron states in ZnO grain boundaries. Our results provide evidence and a microscopic model for room temperature ferromagnetism in oxides.

Electronic Structure and Magnetic Properties of Ti-doped ZnO

2009 ◽  
Vol 1183 ◽  
Author(s):  
Soumia Lardjane ◽  
Ghouti Merad ◽  
Houda Imane Faraoun
Keyword(s):  
Density Functional ◽  
Room Temperature ◽  
Magnetic Semiconductor ◽  
Magnetic Element ◽  
Functional Theory ◽  
Magnetic Structures ◽  
Spintronic Devices ◽  
The Density Functional Theory ◽  
Doped Zno ◽  
Ferromagnetic Ordering

AbstractRecent experiments suggest that Ti doped ZnO can be a promising room temperature dilute magnetic semiconductor (DMS) and a potentially useful material for spintronic devices. Furthermore, the fact that Ti doped ZnO shows ferromagnetic behaviour despite it contains no magnetic element makes this system good candidate for theoretical investigation regarding the controversies about the origin of ferromagnetic ordering in TM-doped ZnO. In this work, the density functional theory (DFT) is used to calculate the electronic and magnetic structures of Ti-doped ZnO. The obtained results are used to discuss the origin of the ferromagnetism, and the contribution of different atoms in the magnetic moment.

scholarly journals First-Principles Investigation of Structural, Electronic, and Room Temperature Ferromagnetism in Si-Doped Monolayer BN

2021 ◽  
Vol 2021 ◽  
pp. 1-8
Author(s):  
Ahemedin Abedea Ajaybu ◽  
Sintayehu Mekonnen Hailemariam
Keyword(s):  
Density Functional ◽  
Room Temperature ◽  
Structural Parameters ◽  
Room Temperature Ferromagnetism ◽  
Total Density ◽  
Ferromagnetic Transition ◽  
Functional Theory ◽  
Spin Polarized ◽  
Si Doped ◽  
Total Density Of States

We performed spin-polarized density functional theory (DFT) to investigate the structural, electronic, and magnetic properties of silicon- (Si-) doped monolayer boron nitride (BN). The present study revealed that structural parameters like bond length, bond angle, and lattice parameters increase as Si-doped in the B site of monolayer BN. However, the bandgap of monolayer BN is reduced in the presence of the Si dopant. Moreover, the obtained magnetic moment and analysis of the total density of states (TDOS) show that Si-doped monolayer BN displays ferromagnetism. The calculated ferromagnetic transition temperature (Tc) value for Si concentration of 12.5% is 476 K which exceeds room temperature. The findings are avenues to enhance the application of monolayer BN for spintronics.

Effect of oxygen on the magnetic property of Bis(8-hydroxyquinoline)copper (CuQ2): An experimental and theoretical study

2015 ◽  
Vol 29 (25n26) ◽  
pp. 1542027 ◽  
Author(s):  
Feng Jiang ◽  
Huimin Yuan ◽  
Wanfeng Xie ◽  
Zhiyong Pang ◽  
Shenghao Han
Keyword(s):  
Dft Calculations ◽  
Density Functional ◽  
Room Temperature ◽  
Room Temperature Ferromagnetism ◽  
Annealed Film ◽  
Energy Difference ◽  
Functional Theory ◽  
Out Of Plane ◽  
The Fourier Transform ◽  
Effect Of Oxygen

The magnetic properties of bis(8-hydroxyquinoline)copper ([Formula: see text]) were investigated by experiments and first-principles density functional theory (DFT) calculations. The as-prepared [Formula: see text] film shows paramagnetic behavior. After annealing in air, room temperature ferromagnetic (FM) properties were found in [Formula: see text] film. The Fourier transform infrared spectroscopy (FTIR) analysis indicates a new vibrational mode related to out of plane O–H bend in the annealed film. DFT calculations show that the energy difference between the FM and the antiferromagnetic (AFM) states is greatly increased after O doping, which may be responsible for the room temperature ferromagnetism in the annealed [Formula: see text] film.

scholarly journals Nitrogen-induced ferromagnetism in BaO

RSC Advances ◽  
2015 ◽  
Vol 5 (42) ◽  
pp. 33674-33680 ◽  
Author(s):  
Gul Rahman
Keyword(s):  
Density Functional Theory ◽  
Spin Density ◽  
Density Functional ◽  
Room Temperature ◽  
Room Temperature Ferromagnetism ◽  
Local Spin Density Approximation ◽  
Density Approximation ◽  
Functional Theory ◽  
Local Spin

Density functional theory with local spin density approximation has been used to propose possible room temperature ferromagnetism in N-doped NaCl-type BaO.

Chalcopyrite Magnetic Semiconductors: An AB–Initio Study of Their Structural, Electronic and Magnetic Properties

2001 ◽  
Vol 674 ◽  
Author(s):  
S. Picozzi ◽  
A. Continenza ◽  
W. T. Geng ◽  
Y. J. Zhao ◽  
A. J. Freeman
Keyword(s):  
Magnetic Properties ◽  
Density Functional ◽  
Room Temperature ◽  
Magnetic Semiconductors ◽  
Room Temperature Ferromagnetism ◽  
Slight Reduction ◽  
Functional Theory ◽  
Electronic And Magnetic Properties ◽  
Anion Substitution ◽  
Mn Concentration

ABSTRACTStimulated by recent experimental observations of room{temperature ferromagnetism of MnxCd1−xGeP2, we investigate the structural, electronic and magnetic properties of these systems as a function of Mn concentration by means of first–principles density-functional-theory-based codes. Moreover, we investigate the effect of the anion substitution (P vs As) in Mn-rich chalcopyirites. Our calculations indicate that the antiferromagnetic alignment is the most stable ordering for all the systems studied, at variance with that experimentally reported. Moreover, we find that there is a slight reduction of the total magnetic moment per Mn atom from ∼5 µB in all the Cd-rich P-based chalcopyrites to ∼4 µB in the Mn–rich MnGeP2 and MnGeAs2 systems.

scholarly journals Metal-Rich Metallaboranes: Synthesis, Structures and Bonding of Bi- and Trimetallic Open-Faced Cobaltaboranes

Inorganics ◽  
2021 ◽  
Vol 9 (4) ◽  
pp. 28
Author(s):  
Kriti Pathak ◽  
Chandan Nandi ◽  
Jean-François Halet ◽  
Sundargopal Ghosh
Keyword(s):  
Electronic Structures ◽  
Density Functional ◽  
Room Temperature ◽  
Electron Pair ◽  
X Ray Diffraction ◽  
Functional Theory ◽  
X Ray ◽  
Cluster 2 ◽  
Cobalt Center

Synthesis, isolation, and structural characterization of unique metal rich diamagnetic cobaltaborane clusters are reported. They were obtained from reactions of monoborane as well as modified borohydride reagents with cobalt sources. For example, the reaction of [Cp*CoCl]2 with [LiBH4·THF] and subsequent photolysis with excess [BH3·THF] (THF = tetrahydrofuran) at room temperature afforded the 11-vertex tricobaltaborane nido-[(Cp*Co)3B8H10] (1, Cp* = η5-C5Me5). The reaction of Li[BH2S3] with the dicobaltaoctaborane(12) [(Cp*Co)2B6H10] yielded the 10-vertex nido-2,4-[(Cp*Co)2B8H12] cluster (2), extending the library of dicobaltadecaborane(14) analogues. Although cluster 1 adopts a classical 11-vertex-nido-geometry with one cobalt center and four boron atoms forming the open pentagonal face, it disobeys the Polyhedral Skeletal Electron Pair Theory (PSEPT). Compound 2 adopts a perfectly symmetrical 10-vertex-nido framework with a plane of symmetry bisecting the basal boron plane resulting in two {CoB3} units bridged at the base by two boron atoms and possesses the expected electron count. Both compounds were characterized in solution by multinuclear NMR and IR spectroscopies and by mass spectrometry. Single-crystal X-ray diffraction analyses confirmed the structures of the compounds. Additionally, density functional theory (DFT) calculations were performed in order to study and interpret the nature of bonding and electronic structures of these complexes.

Sign in / Sign up

Export Citation Format

Share Document