Structural, chemical and magnetic investigations of polycrystalline Zn1−xMnxO

Deshmukh, Alka V.; Patil, S. I.; Yusuf, S. M.; Rajarajan, A. K.; Lalla, N. P.

doi:10.1016/j.jmmm.2009.10.011

Cited by 33 publications

(24 citation statements)

References 35 publications

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“…The lower binding energy (LBE) peak centered *529.9 eV is associated with O 2-ions in Zn-O and Mn-O bonds i.e. lattice oxygen [39,40]. The higher binding energy (HBE) peak *530.9 eV usually associated with O 2-ions in the oxygen-deficient regions in the Zn:MnO matrix [40,41].…”

Section: Resultsmentioning

confidence: 99%

“…lattice oxygen [39,40]. The higher binding energy (HBE) peak *530.9 eV usually associated with O 2-ions in the oxygen-deficient regions in the Zn:MnO matrix [40,41]. The Gaussian deconvolution of O 1 s peak for S 2 has been centered *529.8 and 531.5 eV respectively.…”

Section: Resultsmentioning

confidence: 99%

“…The Gaussian deconvolution of O 1 s peak for S 2 has been centered *529.8 and 531.5 eV respectively. The LBE peak centered at 529.8 eV is attributed to the lattice oxygen (O 2-) [39,40]. The peak observed at higher binding energy (531.5 eV) is related to oxygen vacancies in the oxygen-deficient regions of the material.…”

Section: Resultsmentioning

confidence: 99%

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Magnetic properties of Mn doped ZnO: the role of synthesis route

Karmakar

Neogi

Midya

et al. 2016

J Mater Sci: Mater Electron

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Structural, morphological, optical, magnetic properties and chemical state of the constituent elements of 2 at% Mn doped ZnO samples synthesized by solid state reaction and sol-gel techniques were analyzed. The role of chemical or valency state in tuning the magnetic properties has been investigated. X-ray diffractometer, scanning electron microscope, UV-visible and X-ray photoelectron spectroscopes and superconducting quantum interference device vibrating sample magnetometer (SQUID VSM) were employed for investigation. Mn incorporation in ZnO lattice has been shown by single phase wurtzite structured samples. The presence of defects particularly zinc vacancy (V Zn ) has been evidenced from band tailing. Solid state reaction technique derived sample exhibit strong intrinsic ferromagnetism but sol-gel sample didn't show strong ferromagnetic (FM) ordering. Antiferromagnetic (AFM) interaction is present in both samples. The chemical state of Mn is ?2 for solid state reaction technique derived sample whereas for sol-gel technique derived sample it is a mixed chemical state (exists in both ?2 and ?3 states). Finally, the peculiar magnetic behavior has been interpreted from the interaction between V Zn and d-electrons of Mn 2? and Mn 3? states.

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Section: Resultsmentioning

confidence: 99%

Section: Resultsmentioning

confidence: 99%

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Magnetic properties of Mn doped ZnO: the role of synthesis route

Karmakar

Neogi

Midya

et al. 2016

J Mater Sci: Mater Electron

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“…A large number of reports are available in the literature, both theoretical and experimental; on transition metal ions doped ZnO with contradictory to each other [1][2][3][4][5][6][7][8][9]. Based on the vast experimental data, intrinsic or extrinsic origin of ferromagnetic behavior is studied in Mn doped ZnO with various morphologies, such as bulk [5], films [5,6] and nanoparticles [7] synthesized by the various synthesis methods.…”

Section: Resultsmentioning

confidence: 99%

“…The large amount of experimental work on Mn doped ZnO based DMSs has been reported in literature with contradictory experimental results in favor of RTFM [5][6][7] when processed at lower temperature and against of RTFM [8,9] when processed at higher temperature. Similar results are obtained in different product (bulk and nanoparticles) forms prepared by different synthesis along with different processing parameters [5][6][7][8][9]. In spite of the tremendous amount of experimental work, the origin of RTFM behavior and the associated energy exchange interactions are not fully understood.…”

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confidence: 99%

Structural and Magnetic Behavior of Mn Doped Zno Synthesized By Soft Chemical Route

Bhandarkar¹

2014

IJIRSET

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Nanocrystalline undoped and 5% Mn doped ZnO powders are synthesized by sol-gel route using constituent nitrate and citrate precursors. The physico-chemical characterizations of powders calcined at various temperatures (400-1100 ˚C), are performed using techniques (XRD and SQUID) to study structural, nano/microstructural, and magnetic properties. XRD patterns clearly revealed the evolution of major wurtzite (ZnO) and minor non-stoichiometric defect cubic spinel phase of ZnMnO 3- . Unexpectedly, the magnetic hysteresis loop with its large magnetic parameters are observed at room temperature as soon as the concentration of the minor phase is large enough. The analysis of the unusual room temperature ferromagnetic behavior is presented in this communication based on the dominant contributions of the secondary nanocrystalline non-stoichiometric defect cubic spinel phase of ZnMnO 3- .KEYWORDS: Diluted magnetic semiconductor, soft chemical route, Mn doped ZnO, Room temperature ferromagnetism I. INTRODUCTION In the recent past, a surge of interest is observed in the studies of diluted magnetic semiconductor (DMS) oxides due to simultaneous utilization of charge and spin of electrons in a single material to develop new functionalities [1][2][3][4]. These DMSs are potential candidates for technological application such as spintronic devices. Recently, this class of materials is studied extensively for better understanding of basic mechanisms of different types of magnetic interactions in diluted system. Among these materials, we focused our attention on undoped and doped ZnO based DMS. Dietl et al reported room temperature ferromagnetic (RTFM) behavior arising from carrier mediated exchange interaction has been predicted for several transition metal (Mn, Fe, Co, etc) doped ZnO and GaN DMSs. [2]. The large amount of experimental work on Mn doped ZnO based DMSs has been reported in literature with contradictory experimental results in favor of RTFM [5][6][7] when processed at lower temperature and against of RTFM [8,9] when processed at higher temperature. Similar results are obtained in different product (bulk and nanoparticles) forms prepared by different synthesis along with different processing parameters [5][6][7][8][9]. In spite of the tremendous amount of experimental work, the origin of RTFM behavior and the associated energy exchange interactions are not fully understood. In the present investigation, the RTFM behavior of sol-gel synthesized nanoparticles of 5% Mn doped ZnO is discussed in terms of secondary nanocrystalline defect cubic spinel (DCS) phase of ZnMnO 3- .

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Design and In Situ Growth of Cu₂O‐Blended Heterojunction Directed by Energy‐Band Engineering: Toward High Photoelectrochemical Performance

Zheng

Diao

Zhang

et al. 2022

Adv Materials Inter

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environmental problems. Hydrogen gas (H 2 ) is a clean and storable energy with a higher gravimetric energy density than gasoline (120 vs 44 MJ kg −1 ). Among various hydrogen production strategies, photoelectrochemical (PEC) water splitting has attracted much attention due to its high abundance of water, high purity of generated H 2 , and great reduction of CO 2 emission. [1][2][3][4][5] As the core of the PEC cell, the photoelectrode is composed of a photoanode and a photo cathode, which drives the oxygen evolution reaction (OER, +1.23 V vs reversible hydrogen electrode (RHE)) and hydrogen evolution reaction (HER, 0 V vs RHE), respectively. [1][2][3] At present, both photoanode and photo cathode are facing severe challenges. Among them, photocathode is mainly restricted by the few types of ptype semiconductors (SCs), which need to be improved. Cuprous oxide (Cu 2 O) is one of the most important photocathode materials and has many advantages, such as nontoxicity, element abundant, and high activity. [6,7] It has a narrow direct bandgap of ≈2.0 eV that favors visible light absorption. Its conduction band edge is more negative than −0.7 V versus RHE, providing a large driving force for HER. [6][7][8][9] The theoretical value of photocurrent density is as high as In the field of photoelectrochemical (PEC) water splitting, cuprous oxide (Cu 2 O) is one of the most promising photocathode materials, but its performance is restricted by poor carrier separation ability and low photovoltage. In order to overcome these limitations, a new kind of Cu 2 O-ZnO blended heterojunction photocathode is designed and prepared by novel one-step thermal oxidation method. ZnO granules are uniformly distributed in Cu 2 O film matrix, forming a granular structure, which enhances the band bending of Cu 2 O in the electrolyte and improves the photovoltage. In addition, the formed ladder type band alignment of Cu 2 O-ZnO facilitates the spatial separation of photoexcited carriers. Different from the conventional layered heterojunction, the granular structured heterojunction proposed in this work extends the built-in electric field region and further promotes the transmission of photoexcited carriers from the photoelectrode to the electrolyte. At 0 V vs reversible hydrogen electrode (RHE), the photocurrent density of Cu 2 O-ZnO film is as high as −8.7 mA cm −2 , which is over 6 times that of bare Cu 2 O (−1.3 mA cm −2 ). The onset potential positively shifts from 0.57 V vs RHE to 0.78 V vs RHE. This work provides an effective strategy for improving the PEC performance from the perspective of band alignment and material structure.

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Structural, chemical and magnetic investigations of polycrystalline Zn1−xMnxO

Cited by 33 publications

References 35 publications

Magnetic properties of Mn doped ZnO: the role of synthesis route

Magnetic properties of Mn doped ZnO: the role of synthesis route

Structural and Magnetic Behavior of Mn Doped Zno Synthesized By Soft Chemical Route

Design and In Situ Growth of Cu₂O‐Blended Heterojunction Directed by Energy‐Band Engineering: Toward High Photoelectrochemical Performance

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Structural, chemical and magnetic investigations of polycrystalline Zn1−xMnxO

Cited by 33 publications

References 35 publications

Magnetic properties of Mn doped ZnO: the role of synthesis route

Magnetic properties of Mn doped ZnO: the role of synthesis route

Structural and Magnetic Behavior of Mn Doped Zno Synthesized By Soft Chemical Route

Design and In Situ Growth of Cu2O‐Blended Heterojunction Directed by Energy‐Band Engineering: Toward High Photoelectrochemical Performance

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Design and In Situ Growth of Cu₂O‐Blended Heterojunction Directed by Energy‐Band Engineering: Toward High Photoelectrochemical Performance