Tuning the Magnetic Properties of Metal Oxide Nanocrystal Heterostructures by Cation Exchange

Sytnyk, Mykhailo; Kirchschlager, R.; Bodnarchuk, Maryna I.; Primetzhofer, Daniel; Kriegner, Dominik; Enser, Herbert; Stangl, J.; Bauer, Péter; Voith, Michael; Hassel, Achim Walter; Krumeich, Frank; Ludwig, Frank; Meingast, Arno; Kothleitner, Gerald; Kovalenko, Maksym V.; Heiß, Wolfgang

doi:10.1021/nl304115r

Cited by 104 publications

(119 citation statements)

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“…For example, the previous mentioned one-pot synthesis of FePt/Fe 3 O 4 core/shell nanoparticles where the use of an excess of iron precursor in the synthesis of FePt nanoparticles leads the formation of an iron oxide shell [135][136][137][138] [143,144].…”

Section: Synthesis Of Hard-soft Nanoparticlesmentioning

confidence: 99%

Applications of exchange coupled bi-magnetic hard/soft and soft/hard magnetic core/shell nanoparticles

et al. 2015

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A B S T R A C TThe applications of exchange coupled bi-magnetic hard/soft and soft/hard ferromagnetic core/shell nanoparticles are reviewed. After a brief description of the main synthesis approaches and the core/shell structural-morphological characterization, the basic static and dynamic magnetic properties are presented. Five different types of prospective applications, based on diverse patents and research articles, are described: permanent magnets, recording media, microwave absorption, biomedical applications and other applications. Both the advantages of the core/shell morphology and some of the remaining challenges are discussed.

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Section: Synthesis Of Hard-soft Nanoparticlesmentioning

confidence: 99%

Applications of exchange coupled bi-magnetic hard/soft and soft/hard magnetic core/shell nanoparticles

et al. 2015

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“…These several applications are based on magnetic and electrical behavior of ferrites [1][2][3][4][5][6]. These properties depend on various factors like, ionic radii, nature of hybridization, presence of doped atom in host lattice apart from the particle size [7][8][9][10]. Thus, research is being carried out for doped ferrite systems in order to understand the altered behavior and to optimize them for different applications [11][12][13][14][15].…”

Section: Introductionmentioning

confidence: 99%

Solubility limit, magnetic interaction and conduction mechanism in rare earth doped spinel ferrite

Singh¹,

Kumar²,

Srivastava³

et al. 2016

Appl. Sci. Lett.

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In present review we have focused various issues like solubility limit, magnetic interaction and conduction mechanism of rare earth doped ferrite. Cumulative effects of valence state, magnetic moments of rare earth ions, weakening/strengthening of exchange interaction and magnetic ordering in rare earth ion doped ferrite are responsible for magnetic behavior. It is proposed that characterization techniques based on synchrotron radiation like X-ray absorption spectroscopy and X-ray magnetic circular dichroism can open pathways to prove these assumptions.Keywords: Rare earth, ferrites, magnetic interaction, valence state 1.INTRODUCTIONSpinel ferrites are ferrimagnetic material which have numerous technological applications [1][2][3]. Moreover, nanoparticles of these ferrites are being utilized in high-density magnetic information storage, magnetic resonance imaging, drug delivery etc. [4][5][6]. These several applications are based on magnetic and electrical behavior of ferrites [1][2][3][4][5][6]. These properties depend on various factors like, ionic radii, nature of hybridization, presence of doped atom in host lattice apart from the particle size [7][8][9][10]. Thus, research is being carried out for doped ferrite systems in order to understand the altered behavior and to optimize them for different applications [11][12][13][14][15]. In recent years, rare earth (RE) doped ferrites become interesting due to their superiority for various applications over other doped ferrite systems [17][18][19][20][21][22]. These systems become radioactive and exhibit potentential for biomedical applications [19] along-with efficient tumor passive targeting [23]. Improved capability of dye removal [24], waste water treatment [25], degradation of organic pollutants through photocatalytic activity [26] are other important fields of utilization of these ferrites. These ferrites exhibit enhanced magneto optical kerr (MOKE) effect [20] and excellent microwave absorption properties [21,22]. Thus, these ferrites cover a wide range of applications chiefly based on their magnetic characteristics [17][18][19][20][21][22][23][24][25]. However, there is lack of understanding of magnetic interaction, conduction mechanism inside these ferrites [15,16]. Thus purpose of this review article is to discuss these issues and to give prospects for future research in this direction. SPINEL FERRITEThe general formula for spinel ferrite is MO:Fe2O3 where, M is a divalent transition metal ion. Spinel name is given due to resemblance of structure of these ferrites with mineral spinel MgO.Al2O3. In this structure, oxygen ions are packed quite close together in face centred cubic arrangement and metal ions occupy spaces between them (Fig. 1). These spaces are categorized as tetrahedral (A) and octahedral (B) sites when surrounded by four and six oxygen ions respectively (Fig. 1).In a unit cell of spinel ferrite, there exists 64 and 32 A and B-sites respectively. Only 1/8 th and 1/2 th of A and B-sites are occupied [27]. Metal ions are distributed among A a...

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“…Interestingly, currently, there is an increasing interest in, so-called, inverted structures (see Fig. 1), where the shell is FM or ferrimagnetic (FiM) and the core is AFM, containing for example Mn oxides12131415161718, Fe oxides1920212223242526272829, Co oxides30313233343536, Cr oxides373839, metallic FePt40 or even multiferroic BiFeO 3 (Refs. 41,42).…”

mentioning

confidence: 99%

“…It has been demonstrated, experimentally and theoretically, that the poor crystallinity of the AFM counterpart can result in considerably inferior exchange bias properties4344. In fact, inverted structures have already demonstrated very large coercivities and loop shifts, tunable blocking temperatures, enhanced Néel temperatures or proximity effects12131415161718192021222324252627282930313233343536373839404142 and have been proposed as potential magnetoelectric random access memories41. However, despite their potential, systematic studies of size effects (i.e., core diameter or shell thickness) are still rather scarce12162225333435.…”

mentioning

confidence: 99%

Enhanced Magnetic Properties in Antiferromagnetic-Core/Ferrimagnetic-Shell Nanoparticles

Vasilakaki

Trohidou

Nogués

2015

Sci Rep

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Bi-magnetic core/shell nanoparticles are gaining increasing interest due to their foreseen applications. Inverse antiferromagnetic(AFM)/ferrimagnetic(FiM) core/shell nanoparticles are particularly appealing since they may overcome some of the limitations of conventional FiM/AFM systems. However, virtually no simulations exist on this type of morphology. Here we present systematic Metropolis Monte Carlo simulations of the exchange bias properties of such nanoparticles. The coercivity, HC, and loop shift, Hex, present a non-monotonic dependence with the core diameter and the shell thickness, in excellent agreement with the available experimental data. Additionally, we demonstrate novel unconventional behavior in FiM/AFM particles. Namely, while HC and Hex decrease upon increasing FiM thickness for small AFM cores (as expected), they show the opposite trend for large cores. This presents a counterintuitive FiM size dependence for large AFM cores that is attributed to the competition between core and shell contributions, which expands over a wider range of core diameters leading to non-vanishing Hex even for very large cores. Moreover, the results also hint different possible ways to enhance the experimental performance of inverse core/shell nanoparticles for diverse applications.

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Tuning the Magnetic Properties of Metal Oxide Nanocrystal Heterostructures by Cation Exchange

Cited by 104 publications

References 61 publications

Applications of exchange coupled bi-magnetic hard/soft and soft/hard magnetic core/shell nanoparticles

Applications of exchange coupled bi-magnetic hard/soft and soft/hard magnetic core/shell nanoparticles

Solubility limit, magnetic interaction and conduction mechanism in rare earth doped spinel ferrite

Enhanced Magnetic Properties in Antiferromagnetic-Core/Ferrimagnetic-Shell Nanoparticles

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