Role of defects in enhancing room temperature ferromagnetism of Mn doped ZnO nanoparticles

Ekhande, L. V.; Dhas, Vivek; Kolekar, Y. D.; Ghosh, K.; Date, S. K.; Patil, S. I.

doi:10.1002/pssb.201248567

Cited by 10 publications

(6 citation statements)

References 46 publications

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“…Though the room temperature ferromagnetic ordering in ZnO has controversial origins, intrinsic defects and magnetic impurities and/or impurity phases are the primary causes. − Hence, the type of point defect which is important to induce the ferromagnetism in the prepared NPs is studied well through PL and EPR spectroscopic analysis and confirmed as zinc vacancies. Analogous to the present case, a few research findings are reviewed in the literature. , Particularly, in Mn-doped ZnO, first-principles calculations and X-ray absorption fluorescence spectroscopy (XAFS) studies revealed the existence of singly ionized zinc vacancies which favor the RTFM .…”

Section: Results and Discussionmentioning

confidence: 99%

Diverse Spectroscopic Studies and First-Principles Investigations of the Zinc Vacancy Mediated Ferromagnetism in Mn-Doped ZnO Nanoparticles

Ponnusamy

Selvaraj

Ramachandran

et al. 2016

Crystal Growth & Design

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A systematic study on the room temperature ferromagnetism (RTFM) in undoped and Mn-doped ZnO nanoparticles (NPs) prepared by the coprecipitation method has been reported. The neutral and singly ionized zinc vacancy defects exhibited in the results of photoluminescence (PL), micro-Raman spectroscopy, and electron paramagnetic resonance (EPR) studies are found to be of ferromagnetic origin in bare ZnO, and it has been confirmed that Mn2+ ions substitutionally enter at Zn2+ sites in wurtzite ZnO. The results of positron annihilation and coincidence Doppler broadening measurements corroborate the Zn vacancies and their clusters. It is observed that in Mn:ZnO, the magnetic ordering is changed from ferro- to paramagnetic because of interacting adjacent Mn–Mn ions. The higher saturation magnetization of 565 × 10–3 emu/g is explained by a quasi indirect exchange mechanism based on the interaction of bound magnetic polarons formed by the Zn vacancies (V Zn) and nearby Mn ions. Further, first principle calculations reveal the magnetic centers in nonmagnetic ZnO with V Zn and the stable ferromagnetic ordering in Mn:ZnO at the optimum distance of Mn–Mn ≈ 3.26 Å.

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Section: Results and Discussionmentioning

confidence: 99%

Diverse Spectroscopic Studies and First-Principles Investigations of the Zinc Vacancy Mediated Ferromagnetism in Mn-Doped ZnO Nanoparticles

Ponnusamy

Selvaraj

Ramachandran

et al. 2016

Crystal Growth & Design

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“…Recent studies have shown that applying high field to Mn doped ZnO system would be a crucial factor in order to obtain RTFM behavior and the connection between nanocrystalline secondary phase and magnetism has been thought as and important factor for the RTFM. In our earlier publication, separately synthesized non-stoichiometic DCS-ZnMnO 3- exhibited RTFM with M s = 0.0035 emu g -1 and H c = 22 Oe but with the application of high field as 5 kOe [21].…”

Section: Resultsmentioning

confidence: 92%

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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“…The DC magnetization data for the sample with n = 0.30 collected at 4.5 K and 40 K is presented in Figure 5. The results of the DC magnetization measurements indicated the presence of a hysteresis loop at low temperatures, with a coercive field of approximately 0.2 T at 4.5 K. On the other hand, previous studies have reported superparamagnetic, ferrima netic, and spin-glass behavior of ZnMnO3 nanoparticles [57][58][59]. We attributed the o served magnetic behavior of the calcined ZnO(MnO) samples to the presence of ZnMn nanocrystals, exhibiting superparamagnetic behavior above a blocking temperature ( below 10 K) [36].…”

Section: Magnetic Studiesmentioning

confidence: 78%

“…We attributed the o served magnetic behavior of the calcined ZnO(MnO) samples to the presence of ZnMn nanocrystals, exhibiting superparamagnetic behavior above a blocking temperature ( below 10 K) [36]. Below the blocking temperature, we observed very narrow hystere loops in DC magnetization with very low coercivity values (HC~0.04 T at 4.5 K) for t calcined ZnMnO3 phase [58]. In contrast, the DC magnetization measurements in t work showed much higher coercivity field values, as seen in Figure 5.…”

Section: Magnetic Studiesmentioning

confidence: 79%

Hydrothermal Synthesis and Magnetic Properties of Zn/Mn Oxides Nano Particles

et al. 2023

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The aim of this study was to investigate the magnetic properties of mixed nanocrystalline Zn/manganese oxide compounds synthesized by a hydrothermal method. These compounds are designed as (ZnO)1−n(MnO)n, where index n ranges from 0.05 to 0.60. The results of magnetic measurements, including AC magnetic susceptibility as a function of temperature (up to 160 K) and frequency (from 7 Hz up to 9970 Hz), as well as DC magnetization in magnetic fields up to 9 T and temperature up to 50 K, are reported. We observed various types of magnetic behavior depending on the nominal weight content of MnO. Samples with a low nominal content (up to n = 0.10) of MnO exhibited Curie–Weiss behavior at higher temperatures. For samples with high nominal weight contribution (from n = 0.30 to 0.60), spin-glass-like or/and weak ferromagnetic behavior is observed.

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Role of defects in enhancing room temperature ferromagnetism of Mn doped ZnO nanoparticles

Cited by 10 publications

References 46 publications

Diverse Spectroscopic Studies and First-Principles Investigations of the Zinc Vacancy Mediated Ferromagnetism in Mn-Doped ZnO Nanoparticles

Diverse Spectroscopic Studies and First-Principles Investigations of the Zinc Vacancy Mediated Ferromagnetism in Mn-Doped ZnO Nanoparticles

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

Hydrothermal Synthesis and Magnetic Properties of Zn/Mn Oxides Nano Particles

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