Ferromagnetism in<mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline"><mml:mrow><mml:mi mathvariant="normal">La</mml:mi><mml:mi mathvariant="normal">Co</mml:mi><mml:msub><mml:mi mathvariant="normal">O</mml:mi><mml:mn>3</mml:mn></mml:msub></mml:mrow></mml:math>nanoparticles

Zhou, Shiming; Shi, Lei; Zhao, Jin; He, Liangguo; Yang, Hongbo; Zhang, Shangming

doi:10.1103/physrevb.76.172407

Cited by 78 publications

(71 citation statements)

References 23 publications

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“…The observed trend is consistent with the previous reports for the undoped samples [33][34]. The Curie-like contribution at low temperature increases with an increase in the K concentration.…”

Section: Magnetic-property Measurementssupporting

confidence: 94%

Synthesis and measurement of structural and magnetic properties of K-doped LaCoO3 perovskite materials

et al. 2010

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Polycrystalline La 1−x K x CoO 3 (0 ≤ x ≤ 0.2) rare earth cobaltates have been synthesized by a solution combustion method using glycine as a fuel. The synthesized ceramic materials were characterized by powder X-ray diffraction (XRD), scanning electron microscopy (SEM), Fourier transform infrared spectroscopy (FTIR), and magnetic measurements and studied for physical properties, such as photocatalytic activity. FTIR measurements in conjunction with XRD showed that phases beyond 10% K doping are accompanied by small amounts of impurities. Chemical titrations show the presence of Co 4+ and account for the Co 3+ -Co 4+ mixed-valency of the system. The parent LaCoO 3 shows spin-glass transition at low temperatures, whereas doped samples show transition from spin-glass behavior to paramagnetic ordering on progressive doping of K. "Mixed-conductor" nature of these ceramics positions them as viable candidates for solid oxide fuel cell (SOFC) applications.

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Section: Magnetic-property Measurementssupporting

confidence: 94%

Synthesis and measurement of structural and magnetic properties of K-doped LaCoO3 perovskite materials

et al. 2010

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“…ions. On the other hand, with a decrease in the calcination temperatures, the lattice parameters increased gradually, following an expansion of the cell volume [31]. The change in structure with size reduction could be ascribed to the surface effect producing surface tension [32].…”

Section: Effect Of the Sintering Temperaturesmentioning

confidence: 95%

Synthesis and conductivity properties of Gd0.8Ca0.2BaCo2O5+δ double perovskite by sol–gel combustion

Zhang

Lü

Wei

et al. 2015

J Mater Sci: Mater Electron

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Double perovskite oxides Gd 0.8 Ca 0.2 BaCo 2-O 5?d have been successfully prepared by EDTA-citrate complexation process. The prepared samples were characterized by means of thermogravimetry-differential analysis, X-ray diffraction, Fourier transform infrared spectroscopy techniques. These analyses suggested that pure Gd 0.8 Ca 0.2 BaCo 2 O 5?d phase could be formed when the pH value was maintained above three and calcination temperature was higher than 850°C. The conductivity properties analyzed by means of four probes method, scanning electron microscopy and X-ray photoelectron spectroscopy indicated an improvement in conductivity with a high value of nearly 1200 S/cm, which was due to an increase in the number of small polaron hopping conduction units, Co 3? -O-Co 4? . Interestingly, the Gd 0.8-Ca 0.2 BaCo 2 O 5?d samples exhibited a semiconducting behavior through a wide range of temperature below 100°C and a metallic behavior at 100-500°C, thereby demonstrating that Gd 0.8 Ca 0.2 BaCo 2 O 5?d could meet the requirements of a smart material.

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“…However, a nonlinear M (H) curve and a hysteresis loop were observed at low temperatures, and later a ferromagnetic order around 85 K was reported in small single crystals, nano particles, thin films. [26][27][28][29][30][31] A large variety of lattice defects has been proposed to account for the observed moment in the S = 0 state at low temperatures, such as crystal surface, twin boundary, local strain field, oxygen vacancies. The strong similarity between Ba 2 YIrO 6 and LaCoO 3 with respect to the defect induced magnetism suggests that the important effect of lattice defects on local moments is a general phenomena in J = 0 and S = 0 compounds.…”

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confidence: 99%

Magnetism out of antisite disorder in the J=0 compound Ba2YIrO6

et al. 2017

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We systematically investigate the magnetic properties and local structure of Ba2YIrO6 to demonstrate that Y and Ir lattice defects in the form of antiphase boundary or clusters of antisite disorder affect the magnetism observed in this d 4 compound. We compare the magnetic properties and atomic imaging of (1) a slow cooled crystal, (2) a crystal quenched from 900• C after growth, and (3) a crystal grown using a faster cooling rate than the slow cooled one. Atomic imaging by scanning transmission electron microscopy (STEM) shows that quenching from 900• C introduces antiphase boundary to the crystals, and a faster cooling rate during crystal growth leads to clusters of Y and Ir antisite disorder. STEM study suggests the antiphase boundary region is Ir-rich with a composition of Ba2(Y1−xIrx)IrO6. The magnetic measurements show that Ba2YIrO6 crystals with clusters of antisite defects have a larger effective moment and a larger saturation moment than the slow-cooled crystals. Quenched crystals with Ir-rich antiphase boundary shows a slightly suppressed saturation moment than the slow cooled crystals, and this seems to suggest that antiphase boundary is detrimental to the moment formation. Our DFT calculations suggest magnetic condensation is unlikely as the energy to be gained from superexchange is small compared to the spin-orbit gap. However, once Y is replaced by Ir in the antisite disordered region, the picture of local non-magnetic singlets breaks down and magnetism can be induced. This is because of (a) enhanced interactions due to increased overlap of orbitals between sites, and, (b) increased number of orbitals mediating the interactions. Our work highlights the importance of lattice defects in understanding the experimentally observed magnetism in Ba2YIrO6 and other J = 0 systems.

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Ferromagnetism inLaCoO3nanoparticles

Cited by 78 publications

References 23 publications

Synthesis and measurement of structural and magnetic properties of K-doped LaCoO3 perovskite materials

Synthesis and measurement of structural and magnetic properties of K-doped LaCoO3 perovskite materials

Synthesis and conductivity properties of Gd0.8Ca0.2BaCo2O5+δ double perovskite by sol–gel combustion

Magnetism out of antisite disorder in the J=0 compound Ba2YIrO6

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