Observation of high ferromagnetic ordering in Fe implanted ZnO at room temperature

Author(s):  
D. Sanyal ◽  
Mahuya Chakrabarti ◽  
Vaishali Naik ◽  
Tapatee Kundu Roy ◽  
Debasis Bhowmick ◽  
...  
2009 ◽  
Vol 1183 ◽  
Author(s):  
Soumia Lardjane ◽  
Ghouti Merad ◽  
Houda Imane Faraoun

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.


2019 ◽  
Vol 5 (1) ◽  
Author(s):  
Jian Xu ◽  
Changsong Xu ◽  
Jian-Bo Liu ◽  
Laurent Bellaiche ◽  
Hongjun Xiang ◽  
...  

AbstractHalf-metallic ferromagnets (HMFs) that possess intriguing physical properties with completely spin-polarized current are key candidates for high-efficiency spintronic devices. However, HMFs that could simultaneously have high Curie temperature (Tc), wide half-metallic gap (ΔHM), and large bulk magnetocrystalline anisotropy energy (MAE) are very rare, which significantly restrict their room-temperature (RT) applications. In this article, through materials screening in layered halide double perovskites (LHDPs), we have theoretically identified that Cs4FePb2Cl12, which has good crystallographic, dynamic and thermal stabilities, possesses an intrinsic half-metallic ground-state with a high Tc ~ 450 K. Interestingly, the long-range ferromagnetic ordering in bulk Cs4FePb2Cl12 is contributed by the strong super-superexchange interactions between the neighboring Fe d orbitals mediated by different anionic Cl p orbitals. The high Tc of layered Cs4FePb2Cl12 can be well maintained even in the monolayer limitation, i.e., Tc ~ 370 K for Cs4FePb2Cl12 monolayer, which is critical for nanoscale device applications. Moreover, both bulk and monolayer Cs4FePb2Cl12 can exhibit wide ΔHM ~ 0.55 eV and large MAE >320 μeV/Fe, comparable to that of the best HMFs reported in the literature. Our findings can significantly extend the potentials of LHDPs for high-temperature spintronic applications.


2008 ◽  
Vol 8 (9) ◽  
pp. 4500-4505 ◽  
Author(s):  
Gotluru Kedarnath ◽  
Sandip Dey ◽  
Vimal K. Jain ◽  
Gautam K. Dey ◽  
Ramakant M. Kadam

The Reaction of [HgCl2(tmeda)] with NaTeCH2CH2NMe2 gave a mercury tellurolate, [Hg(TeCH2CH2·NMe2)2] (1) as a yellow crystalline solid, which was characterized by elemental analysis, UV-vis, mass and NMR (1H, 13C, 125Te, 199Hg) spectroscopy. Thermolysis of 1 in hexadecylamine (HDA) at 90 °C in the absence and presence of Mn(OAc)2·4H2O gave undoped and Mn-doped HgTe nanoparticles which were characterized by XRD, EDAX, TEM, EPR and magnetic measurements. These particles could be synthesized with mean particle size of 6–7 nm (from TEM). Manganese substitution at Hg site in HgTe lead to a linear decrease in lattice parameter with increasing concentration of Mn. Magnetization measurements showed ferromagnetic ordering at room temperature with very small coercive field (Hc, 50 Oe) for Hg0.973Mn0.027 Te sample. This sample also exhibited distinct ferromagnetic resonance (FMR) in the EPR spectrum.


2015 ◽  
Vol 30 (S1) ◽  
pp. S97-S100 ◽  
Author(s):  
I. O. Troyanchuk ◽  
M. V. Bushinsky ◽  
V. Efimov ◽  
S. Schorr ◽  
C. Ritter ◽  
...  

Structural measurements have been performed on the La0.7Sr0.3Mn3+0.85Nb5+0.15O3 compound with oxidation state of manganese close to +3. The composition undergoes a structural transition from rhombohedral to orthorhombic symmetry below room temperature. The calculated structural parameters show that the orthorhombic phase is not long-range orbitally ordered and that the structural transition is associated with a steric effect. The compound is ferromagnetic with a Curie point of around 150 K and a magnetic moment of 3.1 μB/Mn. It is suggested that ferromagnetism is originated from superexchange interactions via oxygen. Covalence enhances the positive part of the superexchange interactions whereas structural disorder leads to suppression of ferromagnetism.


2009 ◽  
Vol 1183 ◽  
Author(s):  
Evgeny P. Skipetrov ◽  
Elena A. Zvereva ◽  
Nikolay A. Pichugin ◽  
Alexey E. Primenko ◽  
Evgeny I. Slyn'ko ◽  
...  

Abstract The galvanomagnetic and magnetic properties of novel diluted magnetic semiconductors Pb1-x-yCaxCryTe (x=0.06-0.20, y=0.003-0.045) have been investigated. Temperature dependencies of the resistivity and the Hall coefficient have a metallic character indicating the pinning of Fermi level by the chromium impurity level on the background of the conduction band states. Magnetization curves display a clear hysteresis loop over the whole temperature range investigated. The Curie temperature, determined from the temperature dependencies of magnetization, achieves 345 K. Possible mechanisms of ferromagnetic ordering were discussed.


2013 ◽  
Vol 1552 ◽  
pp. 83-88 ◽  
Author(s):  
Sreekanth K. Mahadeva ◽  
Zhi-Yong Quan ◽  
J. C. Fan ◽  
K. S. Sreelatha ◽  
L. Belova ◽  
...  

ABSTRACTWe report on preliminary studies of low (14 at.%) and high (53at.%) concentration Mn doped MgO films deposited by co-sputtering from metallic Mn and Mg targets. The structural, surface morphologies and magnetic properties of the films of different thickness were studied. All the as grown films are found to be amorphous and film surfaces are found to be flawless and homogeneous. We observe at room temperature robust ferromagnetic loops with a saturation magnetization value that is a function of film thickness reaching a maximum of ∼38.5 emu/cm3 in the Mn0.53Mg0.47O film at a thickness of ∼92 nm. In thicker films room-temperature ferromagnetic ordering is suppressed and eventually at a thickness around 120nm the expected diamagnetism of the bulk appears. The origin of ferromagnetism may be attributed to cation defects at the Mg-site.


2019 ◽  
Vol 9 (1) ◽  
Author(s):  
Nasir Ali ◽  
Vijaya A. R. ◽  
Zaheer Ahmed Khan ◽  
Kartick Tarafder ◽  
Anuvesh Kumar ◽  
...  

AbstractTo develop suitable ferromagnetic oxides with Curie temperature (TC) at or above room temperature for spintronic applications, a great deal of research in doping ZnO with magnetic ions is being carried out over last decade. As the experimental results on magnetic ions doped ZnO are highly confused and controversial, we have investigated ferromagnetism in non-magnetic ion, Ag, doped ZnO. When Ag replaces Zn in ZnO, it adopts 4d9 configuration for Ag2+ which has single unpaired spin and suitable exchange interaction among these spins gives rise to ferromagnetism in ZnO with above room temperature TC. Experimentally, we have observed room temperature ferromagnetism (RTFM) in Ag-doped ZnO with Ag concentration varied from 0.03% to 10.0%. It is shown that zinc vacancy (VZn) enhances the ferromagnetic ordering (FMO) while oxygen vacancy (VO) retards the ferromagnetism in Ag-doped ZnO. Furthermore, the theoretical investigation revealed that VZn along with Ag2+ ions play a pivotal role for RTFM in Ag-doped ZnO. The Ag2+-Ag2+ interaction is ferromagnetic in the same Zn plane whereas anti-ferromagnetic in different Zn planes. The presence of VZn changes the anti-ferromagnetic to ferromagnetic state with a magnetic coupling energy of 37 meV. Finally, it has been established that the overlapping of bound magnetic polarons is responsible for RTFM in low doping concentration. However, anti-ferromagnetic coupling sets in at higher doping concentrations and hence weakens the FMO to a large extent.


Sign in / Sign up

Export Citation Format

Share Document