Predictive study of ferromagnetism and antiferromagnetism coexistence in Ba1-xGdxRuO3 induced by Gd-doping

Some ferromagnetic alloys which adopt the perovskite or double-perovskite structure exhibit some remarkable properties, such as electromagnetic effects, charge and orbital ordering, i.e., dielectric and magnetoresistance effects in the same time. These phenomena are related to both electrical conductivity and spin orbit orientation. In order to optimize and explore the structural, magnetic and electronic properties of GdxBa1-xRuO3 alloy, we investigated here the first-principles calculations using the generalized gradient approximation (GGA+U+SO) as implemented in the Wien2K package. The concentration classification of GdxBa1-xRuO3 alloy with (x = 0, 0.125, 0.25, 0.5, 0.875, 1) is given. In this work, we have identified features such transition phases, spin ordered and charge conduction that enable a priori of both crystal structure and magnetic behavior prediction.Our considerable GdxBa1-xRuO3 alloy is a half-metallic in the cubic phase, and, Mott insulator for x=0.875 and semiconductor for x=1 in the orthorhombic phase. The GdxBa1-xRuO3 alloy therefore undergoes a transition between a cubic phase and another orthorhombic at x = 0.5. It is clear that at this point our alloy (Gd0.5Ba0.5RuO3) is at the same time FM and AFM A-type, in another way, we can say that A-AFM and FM configurations coexist in our alloys. In the case of our GdxBa1-xRuO3 alloy, we can see that the total magnetic moment increases linearly with the concentrations "x" since it has passed from 15.99 μB for x = 0 to 39.95 μB for x = 0.5, this is valid in the cubic phase. That is related to a heavily magnetic moment of spin in the Ru atom which increases also linearly with increasing x, while the magnetic moment of Gd decreases slightly. In the orthorhombic phase, its value remains zero regardless of the concentration because we are in an antiferromagnetic (AF) configuration. The collaboration of the 3d-Ru and 2p-O states is suggested to play an important role for the ferromagnetism in the considered alloy. These orbitals were the most regular in the two bands respectively: the conduction band and the valence band in the two phases given here (cubic and orthorhombic). We also note the mixed collaboration of the states 3d-Ba. On the other hand, the contribution of 3d-Gd states was only effective in the band of conduction, at the time when that of the 4f-Gd states was noticed especially in the orthorhombic phase.

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Understanding complex multiple sublattice magnetism in double double perovskites

Scientific Reports ◽

10.1038/s41598-021-00959-3 ◽

2021 ◽

Vol 11 (1) ◽

Author(s):

Anita Halder ◽

Shreya Das ◽

Prabuddha Sanyal ◽

Tanusri Saha-Dasgupta

Keyword(s):

Magnetic Moment ◽

Double Exchange ◽

Magnetic Behavior ◽

Double Perovskite ◽

Exchange Mechanism ◽

Double Perovskites ◽

Half Metallic ◽

Magnetic Sublattice ◽

High Transition ◽

Interesting Class

AbstractUnderstanding magnetism in multiple magnetic sublattice system, driven by the interplay of varied nature of magnetic exchanges, is on one hand challenging and on other hand intriguing. Motivated by the recent synthesis of AA$$^{\prime }$$ ′ BB$$^{\prime }$$ ′ O$$_6$$ 6 double double perovskites with multiple magnetic ions both at A- and B-sites, we investigate the mechanism of magnetic behavior in these interesting class of compounds. We find that the magnetism in such multiple sublattice compounds is governed by the interplay and delicate balance between two distinct mechanisms, (a) kinetic energy-driven multiple sublattice double exchange mechanism and (b) the conventional super-exchange mechanism. The derived spin Hamiltonian based on first-principles calculations is solved by classical Monte Carlo technique which reproduces the observed magnetic properties. Finally, the influence of off-stoichiometry, as in experimental samples, is discussed. Some of these double double perovskite compounds are found to possess large total magnetic moment and also are found to be half-metallic with reasonably high transition temperature, which raises the hope of future applications of these large magnetic moment half-metallic oxides in spintronics and memory devices.

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First-principles prediction of insulating antiferromagnet in ordered double-perovskite Ca2MnMoO6 compound

International Journal of Computational Materials Science and Engineering ◽

10.1142/s2047684117500270 ◽

2017 ◽

Vol 06 (04) ◽

pp. 1750027 ◽

Cited By ~ 2

Author(s):

A. Djefal ◽

S. Amari ◽

K. O. Obodo ◽

L. Beldi ◽

H. Bendaoud ◽

...

Keyword(s):

Magnetic Moment ◽

Density Functional ◽

Energy Gap ◽

Double Perovskite ◽

Ferromagnetic Phase ◽

Full Potential ◽

Generalized Gradient ◽

Spin Configuration ◽

Metallic Character ◽

Conduction Bands

Using first-principle calculations within the framework of density functional theory (DFT), the full-potential linearized augmented plane-wave (FP-LAPW) method have been performed to investigate structural, electronic and magnetic properties of the Ca2MnMoO6 double perovskite. Different spin configurations (ferromagnetic (FM), ferrimagnetic (FiM), and anti-ferromagnetic AFM1, and AFM2) within both generalized gradient approximation (GGA) and [Formula: see text] (Hubbard Coulomb onsite correction) were considered. The value of the Hubbard−Coulomb [Formula: see text] parameter was varied in the range of [Formula: see text][Formula: see text]eV. The ground state is found to be AFM and insulating with the AFM1 state which is the most favorable. In the AFM1 spin configuration, Ca2MnMoO6 compound has a semiconductor nature, with the fully spin-polarized valence and conduction bands in the same spin channel. Within the [Formula: see text] approximation, the FM phase has a half-metallic character with a net magnetic moment of [Formula: see text] while in the anti-ferromagnetic phase it has an insulating character with zero net magnetic moment which was found at [Formula: see text][Formula: see text]eV. We found that in the AFM phase within the GGA approximation, a metallic character is obtained for Ca2MnMoO6 and also for [Formula: see text][Formula: see text]eV. In particular, for Hubbard [Formula: see text] of 3.6[Formula: see text]eV, a small energy gap of 0.20[Formula: see text]eV is observed. The main features shown by the density of states curves motivate further experimental exploration in the double perovskite Ca2MnMoO6 for spintronic applications.

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Half-metallicity and optoelectronic properties of V-doped zincblende ZnS and CdS alloys

International Journal of Modern Physics B ◽

10.1142/s021797921650034x ◽

2016 ◽

Vol 30 (08) ◽

pp. 1650034 ◽

Cited By ~ 9

Author(s):

Mohammed El Amine Monir ◽

H. Baltache ◽

R. Khenata ◽

G. Murtaza ◽

R. Ahmed ◽

...

Keyword(s):

Magnetic Moment ◽

Density Functional ◽

Spin Exchange ◽

Electronic Band Structure ◽

Magnetic Behavior ◽

Full Potential ◽

Generalized Gradient ◽

Half Metallicity ◽

Electronic Band ◽

Half Metallic

In this paper, spin-polarized density functional calculations on the structural, electronic, optical and magnetic properties of the zincblende structure of the [Formula: see text] and [Formula: see text] alloys at [Formula: see text] in the ferromagnetic (FM) ordering has been investigated. The study is accomplished using the full-potential (FP) linearized augmented plane wave plus local orbital (LAPW[Formula: see text]lo) self-consistent scheme of calculations. To incorporate the exchange correlation component in the total energy calculations of the crystal, Perdew–Burke and Ernzerhof (PBE) parameterization for the generalized gradient approximation (GGA) and GGA[Formula: see text]U are employed. Basically, for both alloys, to address their structural properties, we calculated their equilibrium lattice constants, bulk moduli as well as pressure derivatives. In general, from the analysis of the obtained electronic band structure of these alloys, the half-metallic nature of [Formula: see text] and nearly half-metallic nature of the [Formula: see text] alloy are demonstrated. The plotted density of states (DOS) curves project spin-exchange splitting energy [Formula: see text] and [Formula: see text] as generated by V-3d states. It has been clearly evident that the effective potential results for the spin-down case are more striking than for the spin-up case. In order to describe the magnetic behavior of these alloys, the exchange constants [Formula: see text] (valence band) and [Formula: see text] (conduction band) as well as the magnetic moment values are estimated. The calculated results of the magnetic moment show that the main source in the reduction of the local magnetic moment of V in the alloys in comparison with its free value is a [Formula: see text]–[Formula: see text] orbital hybridization and partial transfer to nonmagnetic sites of (Zn, S) and (Cd, S) in [Formula: see text] and [Formula: see text] alloys. In addition, a study concerning optical properties, such as the refractive index, reflectivity and absorption coefficients is performed to determine their potential for optical and optoelectronic devices.

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Annealing effect on the optical and photoelectrochemical properties of lead oxide

The European Physical Journal Applied Physics ◽

10.1051/epjap/2018180263 ◽

2018 ◽

Vol 84 (3) ◽

pp. 30301 ◽

Cited By ~ 2

Author(s):

Wided Zerguine ◽

Djamila Abdi ◽

Farid Habelhames ◽

Meriem Lakhdari ◽

Hassina Derbal-Habak ◽

...

Keyword(s):

Lead Oxide ◽

Orthorhombic Phase ◽

Heat Treatments ◽

Photoelectrochemical Properties ◽

X Ray Diffraction ◽

Vis Spectroscopy ◽

Size And Morphology ◽

Two Phases ◽

P Type ◽

The Relationship

Effect of the annealing oxidation time of electrodeposited lead (Pb) on the phase formation of lead oxide (PbO) films is reported. The phase structure, optical properties, size and morphology of the films were investigated by scanning electron microscopy, X-ray diffraction and UV-vis spectroscopy. The relationship between structur and photoelectrochemical properties was investigated. Thin films of PbO produced via air annealing of electrodeposited lead consist of a mixture of two phases, orthorhombic (o-PbO) and tetragonal (t-PbO), that determine the material properties and effectiveness as absorber layer in a photoelectrochemical device. The proportion of tetragonal t-PbO increases for longer heat treatments. After 40 h, the sample consists mainly of tetragonal t-PbO. The p-type semiconducting behavior of lead oxide was studied by photocurrent measurements. Different heat treatments yield variations in the ratio of tetragonal to orthorhombic lead oxide that effect on device performances, where devices with a higher content of tetragonal t-PbO show higher photocurrent than with the orthorhombic phase.

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MAGNETIC BEHAVIOR OF IRON IONS IN THE P2O5·CaO GLASS MATRIX

Modern Physics Letters B ◽

10.1142/s0217984903006293 ◽

2003 ◽

Vol 17 (24) ◽

pp. 1271-1275 ◽

Cited By ~ 2

Author(s):

I. ARDELEAN ◽

C. ANDRONACHE ◽

P. PǍŞCUŢǍ

Keyword(s):

Magnetic Susceptibility ◽

High Temperature ◽

Magnetic Moment ◽

Glass Matrix ◽

Magnetic Behavior ◽

Iron Ions ◽

Ion Content ◽

Dipole Interactions ◽

Valence States ◽

Temperature Susceptibility

The temperature dependence of the magnetic susceptibility of x Fe 2 O 3·(100-x)-[ P 2 O 5· CaO ] glasses with 0<x≤50 mol % have been investigated. These data revealed that the valence states and the distribution of iron ions in the glass matrix depend on the Fe 2 O 3 content. For the glasses with x≤1 mol % only Fe 3+ ions are evidenced. In the case of the glasses with 3≤x≤35 mol % both Fe 3+ and Fe 2 ions co-exist in the P 2 O 5· CaO glass matrix, the Fe 2+ ion content is higher than that of the Fe 3+ ions for glasses with x≥10 mol %. For the glasses with x>35 mol %, the evaluated values of the μ eff indicate either the presence of Fe + ions or the coordination influence on the magnetic moment of iron ions, but the presence of small quantities of the antiferromagnetic or ferrimagnetic interactions between iron ions in studied temperature range cannot be excluded. The high temperature susceptibility results indicate that the iron ions are isolated or participate in dipole-dipole interactions for glasses with x≤35 mol % and are antiferromagnetically coupled for higher contents of Fe 2 O 3.

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The Hexagonal ↔ Orthorhombic Structural Phase Transition in Claringbullite, Cu4FCl(OH)6

The Canadian Mineralogist ◽

10.3749/canmin.2000041 ◽

2021 ◽

Author(s):

Mark D. Welch ◽

Jens Najorka ◽

Michael S. Rumsey ◽

John Spratt

Keyword(s):

Phase Transition ◽

Data Storage ◽

Structural Phase Transition ◽

Structural Changes ◽

Structural Phase ◽

Magnetic Behavior ◽

Orthorhombic Phase ◽

New Mineral ◽

Storage Devices ◽

Definition Of

ABSTRACT Frustrated magnetic phases have been a perennial interest to theoreticians wishing to understand the energetics and behavior of quasi-chaotic systems at the quantum level. This behavior also has potentially wide applications to developing quantum data-storage devices. Several minerals are examples of such phases. Since the definition of herbertsmithite, Cu3ZnCl2(OH)6, as a new mineral in 2004 and the rapid realization of the significance of its structure as a frustrated antiferromagnetic phase with a triangular magnetic lattice, there has been intense study of its magnetic properties and those of synthetic compositional variants. In the past five years it has been recognized that the layered copper hydroxyhalides barlowite, Cu4BrF(OH)6, and claringbullite, Cu4FCl(OH)6, are also the parent structures of a family of kagome phases, as they also have triangular magnetic lattices. This paper concerns the structural behavior of claringbullite that is a precursor to the novel frustrated antiferromagnetic states that occur below 30 K in these minerals. The reversible hexagonal (P63/mmc) ↔ orthorhombic (Pnma or Cmcm) structural phase transition in barlowite at 200−270 K has been known for several years, but the details of the structural changes that occur through the transition have been largely unexplored, with the focus instead being on quantifying the low-temperature magnetic behavior of the orthorhombic phase. This paper reports the details of the structural phase transition in natural claringbullite at 100−293 K as studied by single-crystal X-ray diffraction. The transition temperature has been determined to lie between 270 and 293 K. The progressive disordering of Cu at the unusual trigonal prismatic Cu(OH)6 site on heating is quantified through the phase transition for the first time, and a methodology for refining this disorder is presented. Key changes in the behavior of Cu(OH)4Cl2 octahedra in claringbullite have been identified that suggest why the Pnma structure is likely stabilized over an alternative Cmcm structure. It is proposed that the presence of a non-centrosymmetric octahedron in the Pnma structure allows more effective structural relaxation during the phase transition than can be achieved by the Cmcm structure, which has only centrosymmetric octahedra.

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Symmetric Electrodes for Solid Fuel Cells Based on Sr-Doped LaFe0.7Ni0.3O3-δ

Materials Science Forum ◽

10.4028/www.scientific.net/msf.887.24 ◽

2017 ◽

Vol 887 ◽

pp. 24-31

Author(s):

Omar Ben Mya ◽

Mahmoud Omari ◽

Lucia dos Santos-Gomez ◽

David Marerro-Lopezd

Keyword(s):

Fuel Cells ◽

Solid Fuel ◽

Chemical Reactivity ◽

Orthorhombic Phase ◽

Rietveld Analysis ◽

Cubic Phase ◽

Total Conductivity ◽

Sem Images ◽

Low Frequencies ◽

X Ray

Perovskite La1-xSrxFe0.7Ni0.3O3-δ with x = 0.0, 0.1 &0.2 denoted LSFNx has been investigated as potential symmetrical electrode in solid fuel cells (SOFCs). The crystal structure is in pure orthorhombic phase for x = 0.0, orthorhombic-cubic phase coexist for x = 0.1 and pure cubic phase for x = 0.2. Structural properties are studied by X-ray powder diffraction (XRPD), refined by Rietveld analysis. SEM images show the morphology of as prepared and calcined samples either the compatibility between those electrodes and LSGM electrolyte in presence of 50% wt of Ce0.8Gd0.2O2-δ, so that, lower chemical reactivity was found. Total conductivity, impedance in high, medium and low frequencies HF, MF and LF respectively, and resistance polarization (Rp) are determined in air. LaFe0.7Ni0.3O3-δ has a good response in all ranges of frequencies but La0.9Sr0.1Fe0.7Ni0.3O3-δ and La0.8Sr0.2Fe0.7Ni0.3O3-δ have response only in HF and MF and exhibit Rp values as low as LaFe0.7Ni0.3O3-δ .

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Structural and Magnetic Properties of Nano Composite (Ni1-xSrx Fe12 O19) Prepared by Sol-gel

NeuroQuantology ◽

10.14704/nq.2021.19.10.nq21152 ◽

2021 ◽

Vol 19 (10) ◽

pp. 20-28

Author(s):

Dhifaf Hussain Hassan ◽

Sabah Jalal Fathi

Keyword(s):

Magnetic Properties ◽

Hysteresis Loop ◽

Quaternary Structure ◽

Sol Gel ◽

Magnetic Hysteresis ◽

Magnetic Hysteresis Loop ◽

Cubic Phase ◽

X Ray Diffraction ◽

Two Phases ◽

Hematite Fe2o3

The compound was prepared by sol-gel method for spontaneous combustion with certain weight ratios (x=0.0,0.1,0.2,0.3,0.4,0.5,0.6,0.7,0.8,0.9), the samples were calcined at a temperature (900oC) for a period of two hours(2h), then studied its structural and magnetic properties.one of the most prominent results that we obtained from the X-ray diffraction technique (XRD) is that compound has several phases. Where the sample (NiFe2O4) appeared to be polycrystalline and the dominant phase in it is the cubic phase, while the other phase is (Hematite)(Fe2O3) A crystal structure rhomboid (Rhombohedral), in addition to these two phases, the phase with the existing quaternary structure appeared (Sr2Fe2O5) its called (Orthorhombic). The results of the magnetic properties that were obtained through the (VSM) device, and one of the most important of these properties is the magnetic hysteresis loop by analyzing the magnetic hysteresis loop at (x=0.3), where the least area of the hysteresis loop or the least width of the hysteresis loop One of the most important parameters of the magnetic properties is the saturation magnetism (μS) and its value ranges from (19.76-3.86) (emu/gr), the highest value was at (X=0.3) and its value is (19.76emu/gr) and in general its value decreases with increasing concentration of strontium. The residual magnetism (Mr) ranges between (7.45-1.58) (emu/gr), where it reached its highest value at (x=0.3) and its value is (7.45emu/gr), and generally its value decreases with increasing concentration of strontium. In addition to that, there is another parameter which is coercion or Magnetic coercivity (Hc) ranges in value (1751.104-209.26) (Oe), reaching its lowest value at (x=0.3), and then increases with increasing strontium concentration until it reaches its highest value at (x=0.9), where it reached its value is (1751.104Oe). The square rate represented by the symbol (μi) has high values. This means that there is a mutual coupling between the soft and hard magnetic phases, which was the highest value at (x=0.3) and its value is (4.93).

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Conventional synthesis of perovskite structured LaTixFe1-xO3: A comprehensive evaluation on phase formation, opto-magnetic, and dielectric properties

International Journal of Materials Research (formerly Zeitschrift fuer Metallkunde) ◽

10.1515/ijmr-2020-8162 ◽

2021 ◽

Vol 112 (9) ◽

pp. 753-765

Author(s):

Ramesh Kumar Raji ◽

Tholkappiyan Ramachandran ◽

M. Muralidharan ◽

R. Suriakarthick ◽

Muthu Dhilip ◽

...

Keyword(s):

Single Phase ◽

Optical Band Gap ◽

Comprehensive Evaluation ◽

Magnetic Behavior ◽

Orthorhombic Phase ◽

Conventional Solid State Reaction ◽

Raman Analysis ◽

Excitonic Absorption ◽

Magnetic And Dielectric Properties ◽

Quantitative Chemical

Abstract Perovskite structured LaTixFe1-xO3 (x = 0, 0.05, 0.15, 0.25) lanthanum ferrites were synthesized by conventional solid-state reaction. The structural Rietveld refinement and Raman analysis were conducted and confirmed that single-phase orthorhombic phase with Pbnm symmetry formed. The positions of the ions and their bonds of these ferrites were investigated. The spherical shaped morphology of these ferrites was examined. The quantitative chemical composition and distribution of these ferrites were confirmed. The excitonic absorption edge was observed at 590 nm; ascribed to the electronic transition from O2p→Fe3d and optical band gap values increased from 1.85– 2.02 eV as Ti concentration increased. The dielectric and magnetic behavior of these ferrites was studied. It is suggested that synthesized LaTixFe1xO3 powders with different properties could be tailored for different requirements.

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