Fundamental Limitations of Half-Metallicity in Spintronic Materials

2014 ◽  
Vol 215 ◽  
pp. 22-27 ◽  
Author(s):  
Alexander Solontsov
Keyword(s):  
Ground State ◽  
Low Frequency ◽  
Zero Point ◽  
Spin Fluctuations ◽  
Half Metallicity ◽  
Half Metallic ◽  
Strong Damping ◽  
Ferromagnetic Metals ◽  
Fundamental Limitations ◽  
Spin Polarized

Zero-point spin fluctuations are shown to strongly influence the ground state of ferromagnetic metals and to impose limitations for the fully spin polarized state assumed in half-metallic ferromagnets, which may influence their applications in spintronics. This phenomenon leads to the low-frequency Stoner excitations and cause strong damping and softening of magnons in magnetoresistive manganites observed experimentally.

Mxene Monolayer Mn2ZnN2: A Promising Robust Intrinsic Half-metallic Nanosheet

2021 ◽  
Author(s):  
Huang Cheng-Cai ◽  
Wang Yang ◽  
Yao Qian ◽  
Dengfeng Li ◽  
Liu Jun
Keyword(s):  
Magnetic Properties ◽  
Magnetic Moment ◽  
Electrode Materials ◽  
Energy Gap ◽  
Two Dimensions ◽  
Half Metallicity ◽  
Half Metallic ◽  
Spin Polarized ◽  
Metallic Ferromagnet ◽  
A Charge

Abstract Two-dimensions half-metallic ferromagnet is more promising in spintronics. In recent years, the half-metallicity and the magnetic properties of the Mxene materials have been the research hotspot of new materials due to their unique crystal characteristics and wide promising applications. In this paper, the geometric structure of the Mxene nanosheet Mn2ZnN2 was optimized, and then its electric and magnetic properties were studied by the first principles calculations. Results show that the Mxene nanosheet Mn2ZnN2 is possibly a kind of robust intrinsic half-metallic nanosheet with the integer magnetic moment 6.00 μB per unit. Its half-metallic character and the magnetic moment mainly come from the spin-polarized Mn-ions induced by the crystal field. If the absolute compression stain is lower 3.0 %, its half-metallicity remains well and the magnetic moment per unit is always 6.00 μB, indicating its half-metallicity and magnetic properties are stable to some extent. More importantly, removing an electron from this nanosheet, its magnetic moment per unit increases from 6.00 μB to 9.00 μB and the half-metallic energy gap of its spin-down subband increase evidently, showing that removing a charge from the nanosheet may improve evidently its half-metallicity and magnetic properties. Therefore, this nanosheet may be one of preferred spintronic electrode materials.

Investigation of the transport, structural and mechanical properties of half-metallic REMnO3 (RE = Ce and Pr) ferromagnets

RSC Advances ◽  
2016 ◽  
Vol 6 (100) ◽  
pp. 97641-97649 ◽  
Author(s):  
Shakeel Ahmad Khandy ◽  
Dinesh C. Gupta
Keyword(s):  
Mechanical Properties ◽  
Ground State ◽  
First Principles ◽  
Perovskite Oxides ◽  
Systematic Investigation ◽  
Ground State Structure ◽  
First Principles Calculations ◽  
State Structure ◽  
Half Metallicity ◽  
Half Metallic

Systematic investigation of the ground state structure, elastic and transport properties, of perovskite oxides REMnO3 (RE = Ce and Pr) has been carried out by first principles calculations. The half-metallicity and ferromagnetism is well explained.

scholarly journals Half metallicity in Cr substituted Fe2TiSn

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
S. Chaudhuri ◽  
D. Salas ◽  
V. Srihari ◽  
E. Welter ◽  
I. Karaman ◽  
...  
Keyword(s):  
Band Structure ◽  
Ground State ◽  
Electrical Transport ◽  
Coupling Parameter ◽  
Electrical Transport Properties ◽  
Magnetic Ground State ◽  
Half Metallicity ◽  
Half Metallic ◽  
X Ray ◽  
Ferromagnetic Ground State

AbstractBand structure tailoring has been a great avenue to achieve the half-metallic electronic ground state in materials. Applying this approach to the full Heusler alloy Fe2TiSn, Cr is introduced systematically at Ti site that conforms to the chemical formula $${\text{Fe}}_{2} {\text{Ti}}_{{1 - x}} {\text{Cr}}_{x}$$ Fe 2 Ti 1 - x Cr x Sn. Compositions so obtained have been investigated for its electronic, magnetic, and electrical transport properties with an aim to observe the half-metallic ferromagnetic ground state, anticipated theoretically for Fe2CrSn. Our experimental study using synchrotron X-ray diffraction reveals that only compositions with $$x \le$$ x ≤ 0.25 yield phase pure L2$$_1$$ 1 cubic structures. The non-magnetic ground state of Fe2TiSn gets dramatically affected upon inclusion of Cr giving rise to a localized magnetic moment in the background of Ruderman–Kittel–Kasuya–Yosida (RKKY) correlations. The ferromagnetic interactions begin to dominate for x = 0.25 composition. Results of its resistivity and magnetoresistance (MR) measurement point towards a half-metallic ground state. The calculation of exchange coupling parameter, $$\hbox {J}_{{ij}}$$ J ij , and orbital projected density of states that indicate a change in hybridization between 3d and 5p orbital, support the observations made from the study of local crystal structure made using the extended X-ray absorption fine structure spectroscopy. Our findings here highlight an interesting prospect of finding half-metallicity via band structure tailoring for wide application in spintronics devices.

scholarly journals Ground-State Cooling of Levitated Magnets in Low-Frequency Traps

2021 ◽  
Vol 126 (19) ◽  
Author(s):  
Kirill Streltsov ◽  
Julen S. Pedernales ◽  
Martin B. Plenio
Keyword(s):  
Ground State ◽  
Low Frequency ◽  
Ground State Cooling

scholarly journals The effect of pressure and alloying on half-metallicity of quaternary Heusler compounds CoMnYZ (Z = Al, Ga, and In)

2016 ◽  
Vol 34 (4) ◽  
pp. 905-915 ◽  
Author(s):  
M. Rahmoune ◽  
A. Chahed ◽  
A. Amar ◽  
H. Rozale ◽  
A. Lakdja ◽  
...  
Keyword(s):  
Magnetic Properties ◽  
Density Functional ◽  
Heusler Alloys ◽  
Band Gaps ◽  
Ferromagnetic Behavior ◽  
Full Potential ◽  
Energy Bands ◽  
Half Metallicity ◽  
Half Metallic ◽  
Electronic And Magnetic Properties

AbstractIn this work, first-principles calculations of the structural, electronic and magnetic properties of Heusler alloys CoMnYAl, CoMnYGa and CoMnYIn are presented. The full potential linearized augmented plane waves (FP-LAPW) method based on the density functional theory (DFT) has been applied. The structural results showed that CoMnYZ (Z = Al, Ga, In) compounds in the stable structure of type 1+FM were true half-metallic (HM) ferromagnets. The minority (half-metallic) band gaps were found to be 0.51 (0.158), 0.59 (0.294), and 0.54 (0.195) eV for Z = Al, Ga, and In, respectively. The characteristics of energy bands and origin of minority band gaps were also studied. In addition, the effect of volumetric and tetragonal strain on HM character was studied. We also investigated the structural, electronic and magnetic properties of the doped Heusler alloys CoMnYGa1−xAlx, CoMnYAl1−xInx and CoMnYGa1−xInx (x = 0, 0.25, 0.5, 0.75, 1). The composition dependence of the lattice parameters obeys Vegard’s law. All alloy compositions exhibit HM ferromagnetic behavior with a high Curie temperature (TC).

SPIN-POLARIZED ATOMIC DEUTERIUM (↓D) IN THE STATIC FLUCTUATION APPROXIMATION (SFA)

2008 ◽  
Vol 22 (03) ◽  
pp. 257-266 ◽  
Author(s):  
A. S. SANDOUQA ◽  
B. R. JOUDEH ◽  
M. K. AL-SUGHEIR ◽  
H. B. GHASSIB
Keyword(s):  
Ground State Energy ◽  
Ground State ◽  
State Energy ◽  
Ideal Gas ◽  
Hard Sphere Model ◽  
Spin Polarized ◽  
Static Fluctuation Approximation ◽  
Static Fluctuation ◽  
Type Potential ◽  
The Ideal

Spin-polarized atomic deuterium (↓D) is investigated in the static fluctuation approximation with a Morse-type potential. The thermodynamic properties of the system are computed as functions of temperature. In addition, the ground-state energy per atom is calculated for the three species of ↓D : ↓D 1, ↓D 2, and ↓D 3. This is then compared to the corresponding ground-state energy per atom for the ideal gas, and to that obtained by the perturbation theory of the hard sphere model. It is deduced that ↓D is nearly ideal.

Nuclear Magnetic Resonance Studies of δ-Stabilized Plutonium

2003 ◽  
Vol 802 ◽  
Author(s):  
N. J. Curro ◽  
L. Morales
Keyword(s):  
Nuclear Magnetic Resonance ◽  
Magnetic Resonance ◽  
Low Frequency ◽  
Lattice Relaxation ◽  
Spin Fluctuations ◽  
Spin Lattice Relaxation ◽  
Cubic Symmetry ◽  
Magnetic Resonance Studies ◽  
Local Distortions ◽  
Nuclear Magnetic

Nuclear Magnetic Resonance studies of Ga stabilized δ-Pu reveal detailed information about the local distortions surrounding the Ga impurities as well as provides information about the local spin fluctuations experienced by the Ga nuclei. The Ga NMR spectrum is inhomogeneously broadened by a distribution of local electric field gradients (EFGs), which indicates that the Ga experiences local distortions from cubic symmetry. The Knight shift and spin lattice relaxation rate indicate that the Ga is dominantly coupled to the Fermi surface via core polarization, and is inconsistent with magnetic order or low frequency spin correlations.

Ferrimagnetic Half-Metallicity of the New Quaternary Heusler Alloy CoCrScIn: FP-LAPW Method

SPIN ◽  
2021 ◽  
Vol 11 (02) ◽  
pp. 2150017
Author(s):  
Halima Hamada ◽  
Keltouma Boudia ◽  
Friha Khelfaoui ◽  
Kadda Amara ◽  
Toufik Nouri ◽  
...  
Keyword(s):  
Magnetic Moment ◽  
Density Functional ◽  
Structural Parameters ◽  
Magnetic Transition ◽  
Plane Waves ◽  
Full Potential ◽  
Half Metallicity ◽  
Metallic Behavior ◽  
Magnetic Transition Temperature ◽  
Half Metallic

The structural, electronic, elastic and magnetic properties of CoCrScIn were investigated using first principle calculations with applying the full-potential linearized augmented plane waves (FP-LAPW) method, based totally on the density functional theory (DFT). After evaluating the results, the calculated structural parameters reveal that CoCrScIn compound is stable in its ferrimagnetic configuration of the type-III structure. The mechanical properties show its brittle and stiffer behavior. The formation energy value showed that CoCrScIn can be experimentally synthesized. Additionally, the obtained band structures and density of states (DOS) reflect the half-metallic behavior of CoCrScIn, with an indirect bandgap of 0.43[Formula: see text]eV. The total magnetic moment of 3[Formula: see text][Formula: see text] and half-metallic ferrimagnetic state are maintained in the range 5.73–6,79 Å. The magnetic moment especially issues from the Cr-[Formula: see text] and Co-[Formula: see text] spin-polarizations. Furthermore, the calculations of Curie temperature reveal that CoCrScIn has high magnetic transition temperature of 836.7[Formula: see text]K.

scholarly journals Free-radical gases on two-dimensional transition-metal disulfides (XS2, X = Mo/W): robust half-metallicity for efficient nitrogen oxide sensors

2018 ◽  
Vol 9 ◽  
pp. 1641-1646 ◽  
Author(s):  
Chunmei Zhang ◽  
Yalong Jiao ◽  
Fengxian Ma ◽  
Sri Kasi Matta ◽  
Steven Bottle ◽  
...  
Keyword(s):  
Free Radical ◽  
Transition Metal ◽  
Density Functional ◽  
Single Layer ◽  
Metal Sulfides ◽  
Half Metallicity ◽  
Functional Theory ◽  
Half Metallic ◽  
Gas Molecules ◽  
High Level

The detection of single gas molecules is a highly challenging work because it requires sensors with an ultra-high level of sensitivity. By using density functional theory, here we demonstrate that the adsorption of a paramagnetic unpaired free radical gas (NO) on a monolayer of XS2 (X = Mo, W) can trigger the transition from semiconductor to half metal. More precisely, the single-layer XS2 (X = Mo, W) with NO adsorbed on it would behave like a metal in one spin channel while acting as a semiconductor in the other spin orientation. The half-metallicity is robust and independent of the NO concentration. In contrast, no half-metallic feature can be observed after the adsorption of other free radical gases such as NO2. The unique change in electronic properties after the adsorption of NO on transition-metal sulfides highlights an effective strategy to distinguish NO from other gas species by experimentally measuring spin-resolved transmission. Our results also suggest XS2 (X = Mo, W) nanosheets can act as promising nanoscale NO sensors.

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