Colloidal Synthesis of Non‐Equilibrium Wurtzite‐Type MnSe

Sines, Ian T.; Misra, R.; Schiffer, P.; Schaak, Raymond E.

doi:10.1002/anie.201001213

Cited by 76 publications

(76 citation statements)

References 20 publications

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“…(2 0 2) crystallographic planes of the hexagonal WZ MnSe structure and are consistent to earlier works [17,18]. The MnSe 2 phase, as evident from the peaks at $23.8 and 31.4 , is likely to exist in the form of trace amount of byproduct [17]. On the other hand, a mixed phase of WZ MnSe, WZ CdSe and cubic CdMnSe can be retrieved for Cd 1 À x Mn x Se QDs, and for x = 0.3 and 0.8.…”

Section: Structural and Morphological Analysis Of Binary And Ternary Qdssupporting

confidence: 90%

“…7(b) depicts a set of M $ H hysteresis plots of the nanoparticle systems with x = 0.3 and 1, measured at 20 K. Essentially, the QDs are paramagnetic in nature. Nevertheless, the T N value in our case (for x = 1) is close to the reported WZ type, spherical shaped and water droplet-shaped MnSe nanoparticles [15,17].…”

Section: Magnetic Characterization Of Synthesized Qdssupporting

confidence: 85%

“…In contrast, MnSe-QDs (for x = 1), characterize diffraction peaks positioned at $25. (2 0 2) crystallographic planes of the hexagonal WZ MnSe structure and are consistent to earlier works [17,18]. The MnSe 2 phase, as evident from the peaks at $23.8 and 31.4 , is likely to exist in the form of trace amount of byproduct [17].…”

Section: Structural and Morphological Analysis Of Binary And Ternary Qdssupporting

confidence: 80%

“…Whereas, a significant blue shift is ascribed to the sp-d exchange interactions between electrons confined in the conduction and valence band electron states and those located in the partially filled Mn 2+ states [8,[24][25][26]. This explanation [27] is also substantiated by the fact that, the replacement of Cd by Mn (in Cd 1Àx Mn x Se, 0.3 < x < 0.8) would vary the energy gap between 1.74 and 3.5 eV, as for the bulk CdSe (x = 0), and the WZ-MnSe (x = 1) systems; respectively [17]. The optical band gap of the QDs with varying stoichiometric parameter x, are highlighted in Table 2.…”

Section: Analysis Through Optical Absorption and Emission Spectroscopmentioning

confidence: 87%

See 3 more Smart Citations

Manifested luminescence and magnetic responses of stoichiometry dependent Cd1− xMnxSe quantum dots

Sarma

Deka

Mohanta

2015

Materials Research Bulletin

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Section: Structural and Morphological Analysis Of Binary And Ternary Qdssupporting

confidence: 90%

Section: Magnetic Characterization Of Synthesized Qdssupporting

confidence: 85%

Section: Structural and Morphological Analysis Of Binary And Ternary Qdssupporting

confidence: 80%

Section: Analysis Through Optical Absorption and Emission Spectroscopmentioning

confidence: 87%

See 2 more Smart Citations

Manifested luminescence and magnetic responses of stoichiometry dependent Cd1− xMnxSe quantum dots

Sarma

Deka

Mohanta

2015

Materials Research Bulletin

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“…There have also been several reports of non-equilibrium phases in semiconductor NPs. [4][5][6][7] For multicomponent metal NPs, metastable phases [8][9][10][11] are well known. In some instances, metastable phases frustrate efforts to obtain equilibrium phases.…”

mentioning

confidence: 99%

Composition‐Mediated Order‐Disorder Transformation in FePt Nanoparticles

Johnston‐Peck

Cullen

Tracy

2013

Part & Part Syst Charact

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While great progress has been made in the synthesis, property optimization, and applications of chemically synthesized functional nanoparticles (NPs), a signifi cant remaining challenge is to uniformly control the composition and phase of multicomponent NPs. Phase equilibria for NPs may be altered from bulk behavior due to the higher proportion of surface atoms and contributions from surface chemistry, such as ligand monolayers, resulting in altered thermodynamic and metastable phases for NPs. For Co [ 1,2 ] and Ag, [ 3 ] new phases have been observed in NPs and nanowires, respectively. There have also been several reports of non-equilibrium phases in semiconductor NPs. [4][5][6][7] For multicomponent metal NPs, metastable phases [8][9][10][11] are well known. In some instances, metastable phases frustrate efforts to obtain equilibrium phases. FePt NPs are such a system, wherein an undesired metastable alloy phase and multiple intermetallic phases have hindered the preparation of intermetallic, phase-pure, chemically synthesized FePt NPs with a monodisperse size distribution. [ 12 ] New insights about these challenges and how to overcome them will also be applicable to other kinds of multicomponent metal NPs.FePt NPs are of interest for bit-patterned media (BPM), a prospective architectural paradigm shift for the magnetic recording industry that overcomes the storage density limits of current recording media by using discrete magnetic bits rather than continuous media. [ 13 ] While reducing the bit size increases the storage density, it also increases bits' susceptibility toward thermal demagnetization, which would cause data loss. Superparamagnetism occurs when thermal energy ( k B T ) is suffi cient to overcome a NP's magnetocrystalline anisotropy energy ( KV ), where K is the magnetocrystalline anisotropy constant and V is the volume, which induces random reorientation of the magnetization direction. Magnetocrystalline anisotropy is the coupling of the moment to a favored crystal direction. Other magnetic anisotropies are known, such as those arising from the NP surface, anisotropic shapes, or strain, but for unstrained NPs of approximately spherical shape, magnetocrystalline anisotropy is usually the predominant magnetic anisotropy. The L1 0 intermetallic phase of FePt has an extremely large K of ≈ 10 7 erg cm −3 , [ 14 ] which makes is attractive for BPM, as well as for permanent magnet applications. [ 12 ] In addition to thermal stability, another requirement for BPM is for the variance in the fi eld required to change the magnetization direction of the bits (commonly referred to as the switching fi eld distribution) to be small, in order to avoid high rates of read and write errors. [ 15 ] A narrow switching fi eld distribution can be achieved with periodically spaced bits that have similar magnetic properties. [16][17][18] Monodisperse FePt NPs synthesized using wet-chemical approaches are stabilized by ligands that facilitate self-assembly into highly ordered structures. [ 8 ] Such methods produce disord...

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Spin Ordering Induced Broadband Photodetection Based on Two‐Dimensional Magnetic Semiconductor α‐MnSe

et al. 2022

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Two‐dimensional (2D) magnetic semiconductors are considered to have great application prospects in spintronic logic devices, memory devices, and photodetectors, due to their unique structures and outstanding physical properties in 2D confinement. Understanding the influence of magnetism on optical/optoelectronic properties of 2D magnetic semiconductors is a significant issue for constructing multifunctional electronic devices and implementing sophisticated functions. Herein, the influence of spin ordering and magnons on the optical/optoelectronic properties of 2D magnetic semiconductor α ‐MnSe synthesized by space‐confined chemical vapor deposition (CVD) is explored systematically. The spin‐ordering‐induced magnetic phase transition triggers temperature‐dependent photoluminescence spectra to produce a huge transition at Néel temperature ( T N ≈ 160 K). The magnons‐ and defects‐induced emissions are the primary luminescence path below T N and direct internal 4 a T 1g → 6 A 1g transition‐induced emissions are the main luminescence path above T N . Additionally, the magnons and defect structures endow 2D α ‐MnSe with a broadband luminescence from 550 to 880 nm, and an ultraviolet–near‐infrared photoresponse from 365 to 808 nm. Moreover, the device also demonstrates improved photodetection performance at 80 K, possibly influenced by spin ordering and trap states associated with defects. These above findings indicate that 2D magnetic semiconductor α ‐MnSe provides an excellent platform for magneto‐optical and magneto‐optoelectronic research.

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Colloidal Synthesis of Non‐Equilibrium Wurtzite‐Type MnSe

Cited by 76 publications

References 20 publications

Manifested luminescence and magnetic responses of stoichiometry dependent Cd1− xMnxSe quantum dots

Manifested luminescence and magnetic responses of stoichiometry dependent Cd1− xMnxSe quantum dots

Composition‐Mediated Order‐Disorder Transformation in FePt Nanoparticles

Spin Ordering Induced Broadband Photodetection Based on Two‐Dimensional Magnetic Semiconductor α‐MnSe

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