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At least 775 records · Page 43
All sourcesNASA NTRSDOE OSTI
DOE OSTI2018

Structural, Optical, and Magnetic Properties of Gd-Doped TiO{sub 2} Nanoparticles

Polycrystalline pure and (1, 3 and 5%) Gd-doped TiO{sub 2} nanoparticles were synthesised by simple sol-gel method. The structure, morphology and physico-chemical properties of samples were characterised by X-ray diffraction, Fourier transform infrared spectroscopy, Raman spectra, transmission electron microscopy and N{sub 2} absorption and desorption isotherms. Photoluminescence (PL) measurements revealed that the samples exhibit extended light absorption frequencies in visible light region. The visible emission of TiO{sub 2} is found to be largely dependent on the defects and which were found to be tailored by varying Gd doping concentration. Room temperature magnetic studies reveal the transition from ferromagnetic to paramagnetic nature which occurs due to the high magnetic moment of Gd ions and its interaction with host lattice.

75 CONDENSED MATTER PHYSICS, SUPERCONDUCTIVITY AND↗
DOE OSTI2019

Structural, Vibrational, and Magnetic Properties of MoS{sub 2}/Cr{sub 2}O{sub 3} Composites Synthesized by the Solid-State Technique

(1− x) Cr{sub 2}O{sub 3}/x MoS{sub 2} (x = 0.25, 0.5, 0.75) were synthesized using the powder solid-state route. The structural, morphological, vibrational, and magnetic properties of the as-prepared MoS{sub 2}/Cr{sub 2}O{sub 3} samples with different Cr{sub 2}O{sub 3} contents have been studied by X-ray diffraction (XRD), scanning electron microscopy (SEM), infrared spectroscopy, Raman spectroscopy, and vibrating sample magnetometry (VSM), respectively. The X-ray diffraction results show the presence of the parent compounds (molybdenum disulfide (MoS{sub 2}) and chromium oxide (Cr{sub 2}O{sub 3})) in addition to a secondary phase corresponding to chromium molybdenite Cr{sub 2}Mo{sub 3}O{sub 12}. Raman and IR spectra were recorded, and the observed modes were analyzed and assigned to different normal modes of vibration. Magnetic characterizations revealed that all the series MoS{sub 2}/Cr{sub 2}O{sub 3} composites possess paramagnetic characteristics both at room temperature and at 30 K. Further, the maximum of magnetization increased with the increase of Cr{sub 2}O{sub 3} content.

75 CONDENSED MATTER PHYSICS, SUPERCONDUCTIVITY AND↗
DOE OSTI2019

Effect of Ce{sup 3+} Ion on Structural and Hyperfine Interaction Studies of Co{sub 0.5}Ni{sub 0.5}Fe{sub 2−x}Ce{sub x}O{sub 4} Ferrites: Useful for Permanent Magnet Applications

Nanoparticles of Co{sub 0.5}Ni{sub 0.5}Fe{sub 2−x}Ce{sub x}O{sub 4} (where x = 0.0, 0.01, 0.015 and 0.02) ferrites are prepared by the modified solution combustion method using a mixture of fuels and are characterized to understand their structural, microstructural and magnetic properties. The X-ray diffraction is used to confirm the formation of a single-phase cubic spinel structure. The average crystallite sizes are calculated using the Scherrer formula and are found to be less than 50 nm. The microstructural features are obtained by the scanning electron microscopy, and the compositional analysis is done by using the energy-dispersive spectroscopy. The transmission electron microscopy (TEM) investigations show that the synthesized ferrites are made up of very fine spherical nanoparticles. The influence of a rare-earth element (Ce{sup 3+}) on the magnetic properties of the samples was studied using the Mössbauer spectroscopy. The Mössbauer spectroscopy reveals the formation of broadened Zeeman lines and quadrupole-split lines and the presence of the Fe{sup 3+} charge state at B sites in the samples. The quadrupole splitting shows that the orientation of the magnetic hyperfine field with respect to the principle axes of the electric field gradient was random. The magnetic hyperfine field values indicate that the A sites have more A-O-B superexchange interactions than the B sites. The coexistence of magnetic sextet and a doublet component on the room-temperature spectra suggests superparamagnetic properties of the nanoparticles. The low-temperature (15 K) Mössbauer spectroscopy explores the paramagnetic relaxation in the nanoparticles. The area under the sextet refers to Fe{sup 3+} concentrations in the tetrahedral and octahedral sites of the ferrite. This study confirms that the Ce{sup 3+} substitution of Fe{sup 3+} only for octahedron sites causes the decrease in Fe-O-Fe arrangement. The effect of Ce{sup 3+} doping on the magnetic properties of Co{sub 0.5}Ni{sub 0.5}Fe{sub 2}O{sub 4} is examined from the vibrating sample magnetometry (VSM) spectra. Saturation magnetization values are decreased initially and then increased, as result of Ce{sup 3+} doping. This can be explained by Neel’s two-sub-lattice model. Further, the value of coercivity is found to be increasing with increasing Ce{sup 3+} concentration. The obtained results of M-H loop with improved coercivity (from 851 to 1039 Oe) by Ce{sup 3+} doping of Co{sub 0.5}Ni{sub 0.5}Fe{sub 2}O{sub 4} demonstrate the usefulness for permanent magnet applications.

75 CONDENSED MATTER PHYSICS, SUPERCONDUCTIVITY AND↗
DOE OSTI2019

Development of Room-Temperature Ferromagnetism in Nanocomposite CdO Codoped with Al and Gd: Treatment in Hydrogen Atmosphere

Cadmium oxide codoped with Al and Gd ion powders was synthesised by thermal codecomposition of a mixture of complexes of cadmium acetate dihydrate, gadolinium acetate hydrate, and aluminum nitrate nonahydrate. The mass ratio of Al/Cd was fixed while the mass ratio of Gd/Cd varied systematically. The purpose of the present study is to synthesise and study the transparent conducting oxide (TCO) CdO powder having room-temperature ferromagnetic (RT-FM) properties. To realize that purpose, the synthesised Al/Gd-codoped CdO powder was annealed under hydrogen gas with certain conditions. The X-ray diffraction (XRD) method confirmed the formation of a single nanocrystalline structure; thus, both Al/Gd ions were incorporated into CdO lattice forming solid solutions. Magnetic measurements revealed that some of the doped CdO powders gained paramagnetic (PM) properties where the susceptibility increases with increasing dopant Gd content; the measured effective magnetic moment of dopant Gd{sup 3+} was around 8 μ{sub B}. Furthermore, the magnetic energy of the created RT-FM of the codoped CdO samples by hydrogenation was found to be dependent on the Gd% doping level. For hydrogenated CdO powder doped with 3% Gd, the coercivity (H{sub c}) was 195.9 Oe, the remanence (M{sub r}) was 0.77 memu/g, the saturation magnetisation (M{sub s}) was 5.05 memu/g, and the energy product (U{sub m}) was 150.6 merg/g. Thus, the possibility of production of TCO CdO with RT-FM, where magnetic characteristics can be tailored by doping and post treatment under H{sub 2} gas, was proven. Thus, a new potential candidate to be used as a dilute magnetic semiconductor (DMS) was successfully synthesised.

77 NANOSCIENCE AND NANOTECHNOLOGY↗
DOE OSTI2019

Magnetic Exchange Interactions in Geometrically Frustrated Antiferromagnet of ZnCr{sub 2−x}Ga{sub x}O{sub 4}

In this work, the structural and magnetic properties in ZnCr{sub 2−x}Ga{sub x}O{sub 4} were investigated. In ZnCr{sub 2−x}Ga{sub x}O{sub 4}, Ga{sup 3+} ions substitute partial Cr{sup 3+} ions and occupy the B sites. ZnCr{sub 2}O{sub 4} undergoes a paramagnetic-antiferromagnetic transition at 12 K. In ZnCr{sub 2−x}Ga{sub x}O{sub 4}, the antiferromagnetic short-range correlation occurs below 60 K above T{sub N}. The Ga{sup 3+} doping weakens the antiferromagnetic nearest-neighbor exchange interaction (J{sub 1}) and induces ferromagnetic next-nearest-neighbor exchange interaction (J{sub 2}) among the B site magnetic ions. The generation of the ferromagnetic J{sub 2} is ascribed to structure distortion induced by the Ga{sup 3+} doping.

75 CONDENSED MATTER PHYSICS, SUPERCONDUCTIVITY AND↗
DOE OSTI2019

Half-Metallic Ferromagnetism in V-Doped FmP Binary Monopnictide Compounds: an Ab Initio Calculations

The ab initio calculations of the structural phase stability, magnetic phase stability, and electronic and magnetic properties of the FmP binary monopnictides and the half-metallic ferromagnetic properties of their Fm{sub 1−x}V{sub x}P (for x = 0.25, 0.50, 0.75, and 1)-doped alloys have been assured through the spin-polarized density functional theory (DFT), and they are performed by employing the full-potential linearized augmented plane waves plus local orbitals (FP-L/APW + lo) method that is implemented in the WIEN2k package. The exchange and correlation potential is parameterized by the generated gradient approximation (GGA) of Perdew-Burke-Ernzerhof (PBE) scheme. According to the studies of the magnetic phase stability, the fermium monopnictides (FmP) have a paramagnetic regime, while the ferromagnetic behavior appears when we dope this compound with vanadium. Through the ferromagnetic character of all Fm{sub 1−x}V{sub x}P alloys, the spin-polarized band structures and densities of states exhibit a nearly half-metallic character of Fm{sub 0.75}V{sub 0.25}P alloy, whereas Fm{sub 0.50}V{sub 0.50}P, Fm{sub 0.25}V{sub 0.75}P, and VP compounds showed metallic character. Moreover, the total magnetic moment of the three ternary alloys is mainly contributed by Fm and V elements, where the p-d hybridization reduces the atomic magnetic moment of V element from its free space charge and produces feeble magnetic moments on the nonmagnetic P sites.

75 CONDENSED MATTER PHYSICS, SUPERCONDUCTIVITY AND↗
DOE OSTI2019

Tuning the Magnetic Properties of ZnFe{sub 2}O{sub 4} Nanoparticles Through Partial Doping and Annealing

The aim of this study was to investigate the effect of annealing temperature and cobalt cation (Co{sup 2+}) doping on the magnetic properties of zinc ferrite (ZFO) nanoparticles. The nanoparticles were prepared through sol-gel combustion process with citric acid as the fuel. The obtained nanoparticles were annealed at several temperatures from 300 to 1000 °C for 2 h. Spinel formation was proved by X-ray diffraction (XRD) patterns, and the average crystallite size in all samples was estimated between 22 and 32 nm. It is worthwhile to mention that Fe{sub 2}O{sub 3} and ZnO are detected as the medium phases. Meanwhile, Fe{sub 2}O{sub 3} phase transformation to the other allotropes has happened around 400 °C and was characterized via the simultaneous thermal analysis (STA) and XRD. For higher annealing temperatures, diffusion has gradually been completed and, finally, the single phase of spinel structure was prepared at 1000 °C. In addition, field-emission scanning electron microscopy (FESEM) images revealed that the nanoparticle size after annealing was between 30 and 200 nm for the whole samples. The formation of the spinel phase was considered the most important factor on the magnetic properties of ZFO. Cobalt doping, annealing temperature, and also Fe{sub 2}O{sub 3} phase were the main factors on changing magnetic properties. Paramagnetic nanoparticles with higher coercivity for doped samples rather than un-doped samples have been obtained.

77 NANOSCIENCE AND NANOTECHNOLOGY↗
DOE OSTI2019

Magnetocaloric Effect in La{sub 0.67}Ba{sub 0.33}Mn{sub 0.95}Ni{sub 0.05}O{sub 3} Manganite Near Room Temperature

We report the structural, magnetic, and magnetocaloric properties of La{sub 0.67}Ba{sub 0.33}Mn{sub 0.95}Ni{sub 0.05}O{sub 3} (LBMNO) manganite, synthesized by sol-gel method. X-ray diffraction (XRD) analysis using Rietveld refinement showed that this sample crystallizes in the rhombohedral structure with R 3-bar c space group. Fourier transform infrared spectroscopy (FTIR) and scanning electron microscopy (SEM) analysis were used to confirm the structure formation of the LBMNO material. The temperature dependent magnetization data revealed a transition from ferromagnetic (FM) to paramagnetic (PM) phase at T{sub C}= 308 K. Using Arrott plots, it was found that the transition is of a second order. From the measured magnetization data as a function of magnetic applied field, the magnetic entropy change (−ΔS{sub M}) and the relative cooling power RCP have been determined. In the vicinity of T{sub C} (−ΔS{sub M}) reached a maximum value of 2.15 J kg{sup − 1} K{sup − 1} and a large RCP value of about 299 J kg{sup − 1} under 5 T{sup − 1}. This magnetocaloric effect has been analyzed by considering the Landau theory of magnetic phase transition. Consequently, our sample can be considered a promising material in room-temperature magnetic refrigeration.

75 CONDENSED MATTER PHYSICS, SUPERCONDUCTIVITY AND↗
DOE OSTI2019

Doping Effect of Fe Ions on the Structural, Electrical, and Magnetic Properties of SrTiO{sub 3} Nanoceramic Matrix

In the present investigation, strontium titanate nanoceramic was synthesized by incorporating iron (Fe) ion with general formula SrTi{sub 1−x}Fe{sub x}O{sub 3} (x = 0.0, 0.1, 0.2, and 0.4) using sol-gel autocombustion method. The effect of Fe ions on the structural, morphological, electrical, dielectric, and magnetic properties of the prepared matrix has been investigated by various characterization techniques with the appropriate formulation. The structural properties such as phase space, crystallite size (D), and lattice parameter (a) of prepared matrix are calculated by X-ray diffraction (XRD) technique. The functional groups were analyzed by Fourier transform infrared spectroscopy (FT-IR). The surface morphology of the prepared nanoceramic matrix has been determined by using field emission scanning electron microscopy (FE-SEM) analysis. Calculation of average particle size and diffraction patterns was confirmed by using images from transmission electron microscopy (TEM) and selected area electron diffraction pattern (SAED), respectively. An energy dispersive spectrum analysis (EDS) confirmed the compositional stoichiometry in the investigated matrix. Electrical conductivity increased the prepared sample due to the increasing in the Fe concentration and temperature. The dielectric parameters in the frequency range of 30 Hz to 1 MHz were found higher at lower frequencies. The pure SrTiO{sub 3} matrix shows a paramagnetic nature at room temperature, but for a higher concentration of Fe doping was used to observe the weak ferromagnetic nature. Therefore, due to Fe ion concentration, the properties of the prepared matrix have been completely varied and enhancement in the magnetic properties was observed.

77 NANOSCIENCE AND NANOTECHNOLOGY↗
DOE OSTI2019

Spontaneous Magnetization Estimation and Magnetocaloric Effect Study by Means of Theoretical Models in La{sub 0.67}Pb{sub 0.33}MnO{sub 3}

In this work, the dependence of the spontaneous magnetization on temperature of La{sub 0.67}Pb{sub 0.33}MnO{sub 3} manganite has been experimentally estimated from the Arrot plots and from the magnetic entropy change. The magnetocaloric effect (MCE) in this sample has been simulated by the Landau theory and the phenomenological model. Theoretical simulations correlated well with the experimental results. A secondorder ferromagnetic-paramagnetic (FM-PM) phase transition has been proved for La{sub 0.67}Pb{sub 0.33}MnO{sub 3} compound.

75 CONDENSED MATTER PHYSICS, SUPERCONDUCTIVITY AND↗
DOE OSTI2019

Magnetocaloric Effect and Critical Behavior Investigations in La{sub 0.45}Pr{sub 0.2}Sr{sub 0.35}MnO{sub 3} Manganite Oxide

Structural, magnetic, and magnetocaloric effect (MCE) properties and the critical behavior of the La{sub 0.45}Pr{sub 0.2}Sr{sub 0.35}MnO{sub 3} sample prepared by the sol–gel method have been investigated. The X-ray diffraction characterization reveals that our sample crystallizes in the orthorhombic structure with Pnma space group. Magnetization versus temperature measurement shows that our compound exhibits a ferromagnetic–paramagnetic transition. The Curie temperature is found to be 348 K. Close to this temperature, the maximum values of the magnetic entropy change (ΔS{sub M}) and the relative cooling power (RCP) are found to be 2.84 J/kg/K and 230 J/K under µ{sub 0}H = 5 T, respectively. The Arrott plots revealed that this compound exhibits a second-order magnetic phase transition at T{sub C}. The critical behavior has been investigated by several techniques which are the modified Arrott plot method, the Kouvel–Fisher method, and the critical isotherm analysis. The obtained critical exponents β, γ, and δ are consistent with those predictions of the mean-field model. Their reliability was confirmed by Widom’s scaling relation, as well as the universal scaling hypothesis.

36 MATERIALS SCIENCE↗
DOE OSTI2019

Influence of Ce{sup 3+} Ion Doping on Structural and Magnetic Properties of Magnesium Nanoferrite

Pure and rare earth ion Ce{sup 3+}-doped magnesium nanoferrite magnetic particles, i.e., MgFe{sub 2}O{sub 4} and MgCe{sub x}Fe{sub 2−x}O{sub 4} (x = 0.0, 0.025, 0.05, 0.075, and 0.1) were successfully fabricated using sol-gel technique, and qualitative studies were carried out using X-ray diffractometer (XRD), transmission electron microscopy (TEM), Fourier transform infrared spectroscopy (FTIR), high-resolution field-emission scanning electron microscopy (HRFESEM) equipped with energy-dispersive spectroscopy (EDS), vibrating sample magnetometer (VSM), and electron paramagnetic resonance (EPR) techniques. X-ray diffraction analysis confirmed the crystalline phase of the synthesized samples with no extra phase. The crystallite size obtained from W-H plots follow the same trend as calculated using Scherrer method, and the strain decreases with increasing Ce{sup 3+} ion concentration indicating a lesser number of deformities. FTIR spectra revealed the shifting of lower-frequency band to the higher side with the larger radii Ce{sup 3+} ions. HRFESEM images reveal the reduction in stress on doping. No additional impurities are observed in synthesized samples as is confirmed by EDS analysis. The average particle size obtained by TEM are in agreement with XRD analysis. EPR studies showed an increase in g value and line width with doping. Magnetic measurements carried out at room temperature reveals the value of magnetization initially decreases up to x = 0.05 and afterwards increases with the addition of Ce{sup 3+} ions. These properties reveal superparamagnetic nature of cerium-doped magnesium nanoparticles and can be suitable for catalyst and humidity sensors.

77 NANOSCIENCE AND NANOTECHNOLOGY↗
DOE OSTI2019

Structural, Morphological, Raman, and Mössbauer Studies on (La{sub 0.8}Ca{sub 0.2}){sub 1−x}Bi{sub x}FeO{sub 3} (x = 0.0, 0.1, and 0.2) Compounds

(La{sub 0.8}Ca{sub 0.2}){sub 1−x}Bi{sub x}FeO{sub 3} (x = 0.0, 0.1, and 0.2) compounds were prepared by the sol-gel method, using the citric acid route. Structural and microstructural characteristics of the samples were studied by X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), and Raman spectroscopy. Mössbauer spectroscopy was also used for magnetic characterization and structural confirmation of X-ray data. Refinement of XRD patterns indicated that the compounds crystallize in an orthorhombic structure, Pnma space group. The SEM measurements showed that the morphology of the samples is characterized by the existence of large agglomerates, while TEM confirmed the fine particle size. Raman spectra revealed that, when increasing temperature, the level of oxygen species adsorbed at the surface of the particles increases progressively. Room temperature Mössbauer spectroscopy data revealed the existence of two octahedral magnetic sites in the structure of the compounds, which is compatible with XRD data, and a small percentage of a paramagnetic phase in the samples, which increases with Bi-content.

75 CONDENSED MATTER PHYSICS, SUPERCONDUCTIVITY AND↗
DOE OSTI2019

Nickle Concentration Effect on Low Magnetic Field Magnetocaloric Properties for Ni{sub 2+x}Mn{sub 1−x}Ge

Low magnetic field magnetocaloric properties of Ni{sub 2+x}Mn{sub 1−x}Ge near phase transition from a ferromagnetic to a paramagnetic state were investigated theoretically for level of doping x = 0.1 and 0.2. It is shown that the change of Ni content allows the magnetocaloric effect in Ni{sub 2+x}Mn{sub 1−x}Ge to be tunable, which is more practical for construction magnetocaloric refrigeration. Furthermore, the results show that the magnetocaloric properties of Ni{sub 2+x}Mn{sub 1−x}Ge samples are significantly larger and comparable with some magnetocaloric properties of many materials like La{sub 1−x}Cd{sub x}MnO{sub 3}, Gd{sub 1−x}Ca{sub x}BaCo{sub 2}O{sub 5.5}, Ge{sub 0.95}Mn{sub 0.05}, La{sub 1.25}Sr{sub 0.75}MnCoO{sub 6}, Ni{sub 58}Fe{sub 26}Ga{sub 28}, and MnAs films.

36 MATERIALS SCIENCE↗
DOE OSTI2019

The Crystal Structure, Raman Spectra, and Magnetic Properties of HoCrO{sub 3} Annealed in Different Atmospheres

The crystal structure, phonon Raman scattering, and magnetic properties of HoCrO{sub 3} were studied in a way of impacting the oxygen site by annealing treatment in argon and oxygen atmospheres. Although there are no dramatic changes in magnetic properties, a negative magnetization phenomenon below T{sub N} was observed in all prepared HoCrO{sub 3} samples and a certain of lattice distortion was affected due to the variation of Ho–O bond length and Cr–O–Cr bond angle and bond lengths. The Raman spectra exhibit an obvious shift of mode-related Ho ion instead of modes involved with Cr, which unconsciously leads to the variation of effective paramagnetic moments. The magnetic properties were systematically analyzed by Curie-Weiss and modified Curie-Weiss laws. The effective magnetic moment and symmetric and antisymmetric exchange interactions of J{sub e} and D were discussed. The reduced effective magnetic moments in HoCrO{sub 3} and annealed ones demonstrate possible vacancies of Ho and Cr, which was verified by elemental composition tested by energy-dispersive X-ray spectroscopy.

75 CONDENSED MATTER PHYSICS, SUPERCONDUCTIVITY AND↗
DOE OSTI2019

Effects of Nd, Al Doping on the Structure and Properties of BiFeO{sub 3}

The BiFeO{sub 3}(BFO) and Bi{sub 0.95}Nd{sub 0.05}Fe{sub 1-x}Al{sub x}O{sub 3} (x = 0, 0.03, 0.05, 0.075, 0.1) powders were prepared at 200 °C for 24 h by hydrothermal method. The effects of Al doping content on the structure, morphology, magnetic, and photocatalytic properties were studied. X-ray diffraction (XRD) and Fourier transform infrared spectrometer (FTIR) demonstrated the compounds are distorted rhombohedral perovskite structure without any other heterogeneity and structural transition. Field emission scanning electron microscope (FESEM) reflected surface of compounds is a dense, agglomerated sphere. As the concentration of Al{sup 3+} increases, a small part of the spherical crystallites eventually becomes cauliflower shape. Energy-dispersive X-ray (EDS) showed the Bi{sub 0.95}Nd{sub 0.05}Fe{sub 0.95}Al{sub 0.05}O{sub 3} sample mainly consists of five elements (Bi, Fe, O, Nd, Al) and atom radio matched well with the formula. Vibrating sample magnetometer (VSM) integrated in a physical property measurement system (PPMS-9) illustrated introducing Nd{sup 3+} ions into BFO will enhance its magnetism at room temperature. However, with the increase of non-magnetic ion Al{sup 3+} concentration in Bi{sub 0.95}Nd{sub 0.05}Fe{sub 1-x}Al{sub x}O{sub 3} (x = 0, 0.03, 0.05, 0.075, 0.1), the network structure of Fe-O-Fe was destroyed, which led to the decrease of its net magnetization, so that the hysteresis loop shows paramagnetism. The photocatalytic performance of BFO increased initially and decreased afterwards as Al{sup 3+} concentration increased, and the best catalytic performance was achieved at x = 0.05.

75 CONDENSED MATTER PHYSICS, SUPERCONDUCTIVITY AND↗
DOE OSTI2019

Appearance of Griffiths-Like Phase in a New Pyrochlore Compound La{sub 2}Mn{sub 2}O{sub 7−δ}

The La{sub 2}Mn{sub 2}O{sub 7 − δ} compound was prepared using ceramic method. The X-ray diffraction study revealed that this compound crystallized in pyrochlore oxide–type monoclinic structure with the P2/M space group. Concerning the magnetization measurements, they showed a paramagnetic (PM) behavior at high temperature and a ferromagnetic (FM) transition near 167 K. As for the magnetic measurements, they demonstrated the possible existence of a Griffiths-like phase, which was observed for the first time, to our knowledge, in a pyrochlore oxide-type A{sub 2}B{sub 2}O{sub 7}. This originality can be due to the competition between the AFM and FM interactions of the Mn ions, induced by oxygen deficiency. The critical isotherm analyses indicated that the 3D-Heisenberg was the most acceptable model in the case of our compound.

36 MATERIALS SCIENCE↗
DOE OSTI2019

Study of Structural, Electronic, and Magnetic Properties of Cubic Lanthanide Based on Oxide Perovskite-Type NdGaO{sub 3}

Based on the density functional theory (DFT), the full-potential linearized augmented plane wave with local orbital (FP-L/APW+lo) technique is now employed in this approach to understand the structural, electronic, and magnetic properties of simple cubic oxide perovskite NdGaO{sub 3} compound. In all this investigation, the exchange-correlation (XC) energy is selected in the framework of spin-polarized generalized gradient approximation (spin-GGA). The structural analysis unveils that the ferromagnetic (FM) phase is the stable ground state of the cubic NdGaO{sub 3} compound, where the equilibrium lattice parameters (lattice constant (a{sub 0}), bulk modulus (B{sub 0}), and its first pressure derivative (B′)) are determined in both FM and paramagnetic (PM) phases. The spin-polarized electronic properties (band structure and density of states) of the cubic NdGaO{sub 3} oxide perovskite are studied under the platform of equilibrium lattice parameters; this investigation demonstrates the half-metallic behavior of the studied cubic NdGaO{sub 3} compound because the spin-up case displays the metallic nature, whereas the semiconducting character is observed in spin-down case. The magnetic properties reveal that the total magnetic moment of the cubic NdGaO{sub 3} compound is equal to 3 μ{sub B} and its contribution is mostly generated by Nd atoms, whereas feeble local magnetic moments are installed in non-magnetic Ga and O sites. Through the electronic and magnetic results, we conclude that the cubic perovskite NdGaO{sub 3} compound is classified as a half-metallic ferromagnetic material.

36 MATERIALS SCIENCE↗