Elastic behavior of La0.67Ca0.33MnO3:ZrO2 composites

Lalitha, G.; Das, Debashish; Bahadur, D.; Reddy, P. Venugopal

doi:10.1016/j.jallcom.2007.09.097

Cited by 17 publications

(11 citation statements)

References 14 publications

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“…Debye temperature and average sound velocity increase with an increase in additive contents for both PbO and Ta2O5. A linear relationship between average sound velocity and Debye temperature is observed [23,27].…”

Section: Research Articlementioning

confidence: 92%

Influence of additives on the structural, electrical and elastic properties of nanocrystalline MgCuZn ferrites

2015

Appl. Sci. Lett.

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Lead oxide (PbO) and Tantalum pentoxide (Ta2O5) added Mg0.2Cu0.3Zn0.5 Fe2O4 spinel ferrites are prepared by the microwave hydrothermal method. The prepared powders are characterized by powder X-ray diffraction (XRD), Infrared spectroscopy (IR), Transmission electron microscopy (TEM) and Differential scanning calorimeter (DSC). Monophase nanocrystalline ferrites of ~10 to 20nm size are prepared at a lower processing temperature of 160°C/1hour. The ferrites are sintered to a temperature of 900°C using microwave sintering (MW) method. The influence of additives on structure, densification, microstructure and electrical resistivity is studied. The addition of PbO to ferrite improves sintered density and resistivity compared to Ta2O5. The ultrasonic pulse transmission method is used to determine the elastic properties of the sintered ferrites. Elastic moduli such as Young's modulus (E), bulk modulus (B), modulus of rigidity (G), Poisson's ratio (σ) and Debye temperature (θD) are computed from the measured ultrasonic wave velocities. The elastic moduli of ferrite materials increase with PbO and decrease with Ta2O5 content, whereas Poisson's ratio almost remains constant. A linear relationship between Debye temperature and average sound velocity is observed.

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Section: Research Articlementioning

confidence: 92%

Influence of additives on the structural, electrical and elastic properties of nanocrystalline MgCuZn ferrites

2015

Appl. Sci. Lett.

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“…Interestingly, the possibility of lattice contribution to the electron pairing mechanism has been supported by a number of experimental evidences [6,7]. The ultrasonic method, which is sensitive to lattice instabilities and phase transitions, was found to be very useful to probe bulk property changes of ceramic materials such as glasses [8][9][10][11], magnetoresistance materials [12][13][14][15], and also high-temperature superconductors [16-24 and references therein]. In the latter, step-like velocity anomalies above 200 K indicating sudden or unexpected elastic hardening taking place in superconducting samples have been observed in several RE123 [16,17], RE1113 [20] and Bi-based samples [18,21].…”

Section: Introductionmentioning

confidence: 97%

Effect of Ba-site substitution by Sr on ultrasonic velocity and electron–phonon coupling constant of DyBa2−xSrxCu3O7−δ superconductors

Rasih

Yahya

2009

Journal of Alloys and Compounds

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“…It was widely applied in catalyst carrier and thermal barrier fields due to the stability and insulativity. Previous studies have shown that ZrO 2 doping in the perovskite systems can effectively enhance the magnetoresistance . To the best of our knowledge, it is still unexploited of ZrO 2 doping in the half‐metal Fe 3 O 4 nanoparticles by means of the core–shell structural system.…”

Section: Introductionmentioning

confidence: 99%

The Effect of Thickness‐Tunable ZrO₂ Shell on Enhancing the Tunneling Magnetoresistance of Fe₃O₄ Supraparticles

Xie

et al. 2018

Adv Materials Inter

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at room temperature. This degradation is caused admittedly by the reduced spin polarization due to the multiple effects of oxidation, defects, bonding, and surface reconstruction at the surfaces or interfaces of the polycrystal grain boundaries. Comparing to bulk materials, the nanoparticles can produce enhanced extrinsic MR owing to the effect of spin-dependent interface scattering or tunneling through the boundaries. [18] Additionally, the MR can still be increased by core-shell encapsulated structures. For example, an insulating shell coats on the magnetite core. In such a dielectric system, nanometric ferromagnetic particles show giant TMR by spin-dependent tunneling of conducting electrons at the magneticinsulator interfaces. Electrons with spin parallel to the particle magnetization have a bigger probability of tunneling than electrons with antiparallel spin, resulting in an overall lower resistance. Similar MR enhancement has been realized in Fe 3 O 4 @SiO 2 , [19] Fe 3 O 4 @ oleic acid, [20] Fe@Cr, [21] and Fe 3 O 4 @ZnS [22] system. Insulator zirconium dioxide (ZrO 2 ) is a nonmetallic inorganic material and has excellent resistance to acids and alkalis. It was widely applied in catalyst carrier and thermal barrier fields due to the stability and insulativity. Previous studies have shown that ZrO 2 doping in the perovskite systems can effectively enhance the magnetoresistance. [23][24][25] To the best of our knowledge, it is still unexploited of ZrO 2 doping in the half-metal Fe 3 O 4 nanoparticles by means of the core-shell structural system.In this paper, Fe 3 O 4 @ZrO 2 core-shell nanocomposites are prepared with controllable shell thickness and core-size. The pomegranate-like core is obtained and composed of several monocrystals and single-domain Fe 3 O 4 nanocrystals with size <10 nm. The magnetic structure and magnetotransport property of the core-shell nanocomposites are explored. Our results show that the MR is increased to ≈7.5% at 2 kOe in this core-shell system compared to that of pure Fe 3 O 4 nanoparticles ≈4.7%. Moreover, as Zr content increases, the MR first increases and then decreases. This is because the addition of insulated barrier promotes the tunneling effect, which enhances the MR, but with further increase of ZrO 2 thickness, the barrier becomes larger and the electron tunneling becomes difficult, leading to the reduced MR. In addition, the results of Fe 3 O 4 @ZrO 2 with different core sizes show that the MR rises monotonically with a decrease of the size of core. Moreover, for eliminate the possible effect of ZrO 2 permeating into the interior of the pomegranate-like core, fault-cutting is prepared andThe core-shell Fe 3 O 4 @ZrO 2 nanoparticles with controllable shell thickness and core dimensions are synthesized using solvothermal approaches. The introduction of the insulator ZrO 2 shell allows realizing the enhancement of tunneling magnetoresistance (TMR) effect of the functional nanomaterials. The influences of temperature, magnetic field, and shell thickness on the TMR are ...

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Elastic behavior of La0.67Ca0.33MnO3:ZrO2 composites

Cited by 17 publications

References 14 publications

Influence of additives on the structural, electrical and elastic properties of nanocrystalline MgCuZn ferrites

Influence of additives on the structural, electrical and elastic properties of nanocrystalline MgCuZn ferrites

Effect of Ba-site substitution by Sr on ultrasonic velocity and electron–phonon coupling constant of DyBa2−xSrxCu3O7−δ superconductors

The Effect of Thickness‐Tunable ZrO₂ Shell on Enhancing the Tunneling Magnetoresistance of Fe₃O₄ Supraparticles

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Elastic behavior of La0.67Ca0.33MnO3:ZrO2 composites

Cited by 17 publications

References 14 publications

Influence of additives on the structural, electrical and elastic properties of nanocrystalline MgCuZn ferrites

Influence of additives on the structural, electrical and elastic properties of nanocrystalline MgCuZn ferrites

Effect of Ba-site substitution by Sr on ultrasonic velocity and electron–phonon coupling constant of DyBa2−xSrxCu3O7−δ superconductors

The Effect of Thickness‐Tunable ZrO2 Shell on Enhancing the Tunneling Magnetoresistance of Fe3O4 Supraparticles

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The Effect of Thickness‐Tunable ZrO₂ Shell on Enhancing the Tunneling Magnetoresistance of Fe₃O₄ Supraparticles