Vacancy induced p-orbital ferromagnetism in MgO nanocrystallite

Choudhury, Biswajit; Saikia, Ujjal; Sahariah, Munima B.; Choudhury, Arup

doi:10.1016/j.jallcom.2019.153060

Cited by 12 publications

(7 citation statements)

References 69 publications

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“…Therefore, p-state ferromagnetism seems to be assuming relevance in this case. Ferromagnetism due to p electrons in C around the vacancies in Si and C sites or due to trapping of holes in O sites nearest to the vacancies in Mg in MgO nanocrystals were earlier shown [26,27] in SiC and MgO. Oxidization of oxygen and consequent trapping of holes or even molecular O 2 formation was earlier observed [28] in Na 0.6 (Li 0.2 Mn 0.8 )O 2 system during charge-discharging cylces of a battery where Na 0.6 (Li 0.2 Mn 0.8 )O 2 was used as the cathode.…”

Section: Resultsmentioning

confidence: 98%

Charge-transfer-driven enhanced room-temperature ferromagnetism in BiFeO₃/Ag nanocomposite

Chatterjee,

Mishra,

Mukherjee

et al. 2023

Nanotechnology

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We report observation of more than an order of magnitude jump in saturation magnetization in BiFeO3/Ag nanocomposite at room temperature compared to what is observed in bare BiFeO3 nanoparticles. Using transmission electron microscopy together with energy dispersive x-ray spectra (which maps the element concentration across the BiFeO3/Ag interface) and x-ray photoelectron spectroscopy, we show that both the observed specific self-assembly pattern of BiFeO$_3$ and Ag nanoparticles and the charge transfer between Ag and O are responsible for such an enormous rise in room-temperature magnetization. The BiFeO3/Ag nanocomposites, therefore, could prove to be extremely useful for a variety of applications including biomedical.

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Section: Resultsmentioning

confidence: 98%

Charge-transfer-driven enhanced room-temperature ferromagnetism in BiFeO₃/Ag nanocomposite

Chatterjee,

Mishra,

Mukherjee

et al. 2023

Nanotechnology

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“…Similar to conventional RS, the origin of the steep jump in I DS (Figure 2a) and the hysteresis (Figure 2b) in the I DS -V DS characteristics can be attributed to the formation of conductive filaments. In our system, the possible constituents of the filaments are vacancies of Mg and O atoms in MgO, [11,12,[14][15][16]18] diffused Fe atoms in MgO, and B atoms in Ge. RS has been widely observed for MgO.…”

Section: Discussion Of the Transport Mechanismmentioning

confidence: 99%

“…Due to the localized nature of the O-2p orbitals of the defects in wideband-gap oxides, the spin directions of metal vacancies tend to align due to the strong electron-electron correlation, [9,10] which can be strong enough to induce d 0 ferromagnetism due to Zener's double exchange interactions. [11][12][13][14][15][16][17][18][19][20] Thus, using the spin states in conductive d 0 -ferromagnetic filaments allows us to explore new possibilities for the spintronic applications of RS, such as multifunctional resistive-random access memories. However, little research has been conducted on spin states in RS devices.…”

Section: Introductionmentioning

confidence: 99%

Colossal Magnetoresistive Switching Induced by d⁰ Ferromagnetism of MgO in a Semiconductor Nanochannel Device with Ferromagnetic Fe/MgO Electrodes

Ohya,

Tsuruoka,

Kaneda

et al. 2024

Advanced Materials

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Exploring potential spintronic functionalities in resistive switching (RS) devices is of great interest for creating new applications, such as multifunctional resistive random‐access memory and novel neuromorphic computing devices. In particular, the importance of the spin‐triplet state of cation vacancies in oxide materials, which is induced by localized and strong O–2p on‐site Coulomb interactions, in RS devices has been overlooked. d° ferromagnetism sometimes appears due to the spin‐triplet state and ferromagnetic Zener's double exchange interactions between cation vacancies, which are occasionally strong enough to make nonmagnetic oxides ferromagnetic. Here, for the first time, anomalous and colossal magneto‐RS (CMRS) with very high magnetic field dependence is demonstrated by utilizing an unconventional RS device composed of a Ge nanochannel with all‐epitaxial single‐crystalline Fe/MgO electrodes. Our device shows colossal and unusual behavior as the threshold voltage and ON/OFF ratio strongly depend on a magnetic field, which is controllable with an applied voltage. This new phenomenon is attributed to the formation of d0‐ferromagnetic filaments by attractive Mg vacancies due to the spin‐triplet states with ferromagnetic double exchange interactions and the ferromagnetic proximity effect of Fe on MgO. Our findings will allow the development of energy‐efficient CMRS devices with multifield susceptibility.This article is protected by copyright. All rights reserved

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“…Various researchers have reported the magnetic behaviour of MgO nanomaterial due to intrinsic defects and cationic, anionic & composite vacancies. 12,38 Recently, Kaung et al 31 reported their theoretical study on MgO structure by ab-initio method and confirms FM behaviour on the basis of Mg vacancies only. However, Singh et al demonstrated the Mg vacancies that generate near to surface region of MgO thin films, which is the plausible reason for FM ordering.…”

Section: Magnetic Properties (Vsm)mentioning

confidence: 91%

Mg Defect Induced Ferromagnetic Ordering in Li-Doped MgO Nanostructures

Rani

Sheoran

Shukla

et al. 2021

ECS J. Solid State Sci. Technol.

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Magnesium deficient Li-doped MgO nanostructures were fabricated by hydrothermal method to investigate their structural, electronic, and magnetic properties. X-ray diffraction study confirms the single-phase crystallinity and changing the Li concentration (2%, 4% & 6%) in the host matrix of MgO induced strain and increased the crystallite size. Field-effect scanning electron microscopy images show the change in morphology from flakes to prismatic type nanostructures with the variation in Li content. The increase in Mg defects with an increase in Li doping, elucidated by X-ray photoelectron spectroscopy, would be the plausible reason for origin of d0 ferromagnetism and can be explained through (Li1+–VMg–Li1+) exchange interaction mechanism. Also, this increase in Mg defects leads to an increase in the value of saturation magnetization and grain size as well. Furthermore, electron paramagnetic resonance measurements explored the concepts of g-value and line width which are related with Mg defects and super exchange interaction of paramagnetic ions.

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Vacancy induced p-orbital ferromagnetism in MgO nanocrystallite

Cited by 12 publications

References 69 publications

Charge-transfer-driven enhanced room-temperature ferromagnetism in BiFeO₃/Ag nanocomposite

Charge-transfer-driven enhanced room-temperature ferromagnetism in BiFeO₃/Ag nanocomposite

Colossal Magnetoresistive Switching Induced by d⁰ Ferromagnetism of MgO in a Semiconductor Nanochannel Device with Ferromagnetic Fe/MgO Electrodes

Mg Defect Induced Ferromagnetic Ordering in Li-Doped MgO Nanostructures

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Vacancy induced p-orbital ferromagnetism in MgO nanocrystallite

Cited by 12 publications

References 69 publications

Charge-transfer-driven enhanced room-temperature ferromagnetism in BiFeO3/Ag nanocomposite

Charge-transfer-driven enhanced room-temperature ferromagnetism in BiFeO3/Ag nanocomposite

Colossal Magnetoresistive Switching Induced by d0 Ferromagnetism of MgO in a Semiconductor Nanochannel Device with Ferromagnetic Fe/MgO Electrodes

Mg Defect Induced Ferromagnetic Ordering in Li-Doped MgO Nanostructures

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Charge-transfer-driven enhanced room-temperature ferromagnetism in BiFeO₃/Ag nanocomposite

Charge-transfer-driven enhanced room-temperature ferromagnetism in BiFeO₃/Ag nanocomposite

Colossal Magnetoresistive Switching Induced by d⁰ Ferromagnetism of MgO in a Semiconductor Nanochannel Device with Ferromagnetic Fe/MgO Electrodes