- 标题
- 摘要
- 关键词
- 实验方案
- 产品
-
Epitaxial Growth and Magnetic Properties of NiMnAs Films on GaAs Substrates
摘要： Single-phase Ni0.92Mn1.08As films with strained C1b symmetry are grown on GaAs (001) substrates. In addition, a preferred epitaxial configuration of (110)-orientated Ni0.92Mn1.08As on (001)-orientated GaAs is revealed by synchrotron radiation measurement. The magnetic properties of the films are found to be significantly influenced by the growth temperature and the optimized growth temperature is determined to be ～370°C. According to the results of x-ray absorption spectroscopy, these phenomena can be attributed to the variation of the local electronic structure of the Mn atoms. Our work provides useful information for the further investigations of NiMnAs, which is a theoretically predicted half-metal.
关键词： epitaxial growth,half-metal,Heusler alloy,magnetic properties,NiMnAs
更新于2025-09-23 15:22:29
-
Thermodynamic stability, half-metallic and optical nature of graphene-like Mn <sub/>2</sub> Zr <i>Z</i> ( <i>Z</i> = Ge, Si): <i>Ab initio</i> study
摘要： Half-metallic, optical and thermodynamic phase diagrams of two-dimensional Mn2ZrZ (Z = Ge, Si) have been calculated by density functional theory (DFT) framework with full-potential linear augmented plane-wave (FP-LAPW) method. The spin-polarized electronic computations show that these layers have metallic behavior with a spin polarization less than 100%. It is observed that with increasing thickness of the layers, both the thermodynamic and energy stabilities increased, and the graphene-like layers of Mn2ZrGe with a thickness of 7.6955 ?A and Mn2ZrSi with a thickness of 7.551 ?A are completely stable thermodynamically. The optical responses of Mn2ZrZ (Z = Ge, Si) have anisotropy at infrared region versus the optical direction and have high metallic nature in this optical range. The plasmonic frequencies have occurred after the visible edge and the refraction index becomes lower than one after the ultra-violet edge.
关键词： optical property,half-metal,thermodynamic phase diagram,DFT,Graphene-like Mn2ZrZ (Z = Ge, Si)
更新于2025-09-23 15:21:21
-
Half-metallic properties of transition metals adsorbed on WS2 monolayer: a first-principles study
摘要： Given the various applications of half-metals in the spintronics devises, we studied the structural, electronic and magnetic properties of transition-metal (TM) (Cr, Mn, Fe, Co, Ni, and Cu) adatoms on WS2 monolayer by performing first-principles calculations. Based on the adsorption energy, TM atoms prefer to occupy the TW site, above the W atoms, for all the cases. The results indicate that systems of Cr, Mn, Fe, and Co adsorbed on WS2 monolayer are magnetic, while in Ni and Cu atoms adsorbed don’t have any magnetic properties. The TM atoms are adsorbed chemically to the WS2 layer. The obtained values of the total magnetic moment vary from 4 μB to 1 μB in case of Cr to Co adsorption, respectively, which agree with the Slater–Pauling rule. Based on the magnetic moment of 0.00 μB, non-magnetic states are realized for Ni and Cu adsorption. More importantly, the high spin polarization of 100% at the Fermi level is achieved in the Cr, Mn, Fe and Co adsorption, which implies the potential for application in spintronic devices.
关键词： WS2,DFT,Spintronic,Half-metal,transition metal
更新于2025-09-19 17:15:36
-
Spin-polarized optical properties of half-metallic binary XBi (X?=?Ca, Sr and Ba) compounds in zinc blende and wurtzite phases
摘要： In this work, we aim to study the spin-polarized optical properties of the non-transition metal-based binary compounds XBi (X = Ba, Sr and Ca) in the zinc blende and wurtzite phases. The calculations are performed by the developed full-potential augmented plane wave plus local orbitals (FP-L/APW ? lo) method within the spin density functional theory. We used the Perdew–Burke–Ernzerhof (PBE) generalized gradient approximation (PBE-GGA) and the recently modi?ed Becke–Johnson potential (mBJ-GGA) to generate the exchange–correlation potential. The optical constants as the dielectric function, refractive index and extinction coef?cient were calculated and discussed in detail. Our compounds are identi?ed as potential candidates for spintronic applications and high-performance electronic devices, due to their possible half-metallic character. The interband transitions responsible for the structures in the spectra are speci?ed. It is shown that the Bi-p states and (Ca, Sr, Ba)-d states play the major role in optical transitions as initial and ?nal states.
关键词： Ferromagnetism,DFT,Half-metal,Optical properties
更新于2025-09-10 09:29:36
-
Magnetism in monolayer InSe by nonmetal doping: First-principles study
摘要： To develop InSe-based spintronics devices, introducing magnetism into monolayer InSe is essential. In this work, the electronic and magnetic properties of nonmetal (NM) doped (H, B, C, Si, N, P, As, O, S, Te, F, Cl, Br and I) monolayer InSe were investigated by first-principles calculations. The results indicate that atoms from VA, VIA and VIIA groups are possible to substitute Se atoms under In-rich condition. Second, we have found that only the InSe doped with NM acceptors with odd number of valence electrons possesses magnetism. Especially B doped InSe is a half-metal. However, VIIA group doped InSe does not exhibit magnetism due to the In-In covalent bond. This work provides an important guidance for developing spintronic devices on monolayer InSe.
关键词： nonmetal doping,Monolayer InSe,magnetism,half-metal,In-In covalent bond
更新于2025-09-10 09:29:36
-
Imaging Domains in a Zero-Moment Half Metal
摘要： We have a choice of methods for examining domains at the surface of a ferromagnet that depend on probing the stray ?eld distribution, but these methods do not work in antiferromagnets or compensated ferrimagnets, which produce no stray ?eld. The discovery of compensated ferrimagnetic half metals allows for the local magnetization state to be observed directly with polarized light. The example considered here, Mn2RuxGa, has two inequivalent but oppositely aligned Mn sublattices with equal and opposite moments, but only one of them contributes spin-polarized conduction electrons at the Fermi energy. The material looks like an antiferromagnet from the outside, but from the point of view of the electronic structure, it resembles a spin-polarized ferromagnetic metal. The anisotropy axis is perpendicular to the ?lm plane, which allows domains to be imaged directly by polar magneto-optic Kerr effect. The domain structure in a ?lm with a composition of Mn2Ru0.4Ga has been imaged in a Kerr microscope and hysteresis loops have been traced. Domains have dimensions of order 20 μm with meandering domain walls and a fractal dimension D f = 1.85. Our results open new direct imaging possibilities of magnetically ordered materials with no net moment.
关键词： compensated ferrimagnets,Mn2RuxGa (MRG),half metal,Kerr microscopy,Antiferromagnetic domain walls
更新于2025-09-10 09:29:36
-
Atomic ordering, magnetic properties, and electronic structure of Mn<sub>2</sub>CoGa Heusler alloy
摘要： The magnetic properties and atomic arrangement of Mn2CoGa Heusler alloy were investigated experimentally and by theoretical calculations. The magnetic moment derived from spontaneous magnetization at 5 K was 2.06 μB/f.u. and was close to the integer number of the expected value from theoretical calculation and the Slater–Pauling rule predicted by Galanakis et al. The Curie temperature and L21-B2 order-disorder phase transition temperature were 741 and 1047 K, respectively. Powder neutron diffraction experiment results suggested that the atomic arrangement prefers an L21b-type structure rather than that of Hg2CuTi, being consistent with our previous results of high-angle annular dark-field-scanning transmission electron microscopic observations. The magnetic moments obtained were in good agreement with the theoretical values in the model of the L21b-type structure. The density of states obtained by the first-principles calculation combined with the coherent potential approximation in Mn2CoGa with the L21b-type crystal structure maintained the half-metallic character, even though disordering by Mn and Co atoms was introduced.
关键词： powder neutron diffraction,magnetic moment,Half-metal-type ferromagnets,order-disorder phase transition,atomic ordering,Curie temperature
更新于2025-09-09 09:28:46
-
Strain Induced Metal–Insulator Transition of Magnetic SrRuO3 Single Layer in SrRuO3/SrTiO3 Superlattice
摘要： Ferromagnetic phase in a two-dimensional system plays an important role not only in applications but also in studies of phase transition theory. Among numerous ferromagnetic materials, SrRuO3 is famous for its half-metallicity, itinerant ferromagnetism and non-Fermi liquid metalicity. Single layer SrRuO3 in SrRuO3/SrTiO3 (SRO/STO) superlattice has been predicted as a two-dimensional half-metallic ferromagnetic system based on density functional theory (DFT). However, experiments show that metal–insulator transition associated with ferro–antiferromagnetism (FM–AFM) transition occurs when the thickness of SRO is less than 4 u.c. Combining DFT calculations with Monte Carlo simulations, we demonstrate in this work that the bulk ferromagnetic metallicity can be realized in single layer SRO in SRO/STO superlattice by manipulating the strain effect to trigger the metal–insulator transition, achieving two-dimensional (2D) half-metallic SRO thin film beyond the experimental observation of AFM insulator.Our results pave a new route to fulfill the ultrathin spin-polarized-2D electron gas (SP-2DEG).
关键词： superlattice,metal–insulator transition,half-metal,magnetism,2DEG
更新于2025-09-04 15:30:14