Preparation, microstructure, and magnetic properties of bulk nanocrystalline Gd metal

Yue, Ming; Zhang, J. X.; Zeng, Hong; Wang, Keyuan

doi:10.1063/1.2400079

Cited by 26 publications

(19 citation statements)

References 10 publications

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“…Since the substrate (curved surface of amorphous silica here) affects the growth, other choices of geometries and materials such as Mn, Pd, Cr or W would be expected to lead to different magnetic properties. 28 The polycrystalline nature 23 of the samples, randomly grain formations, 10,11,18,23,25 crystal defects 11 and stress 18,25,29 likely act as barriers to achieving high magnetism by distorting the magnetization uniformity.…”

Section: Resultsmentioning

confidence: 99%

“…In recent years Gd nanoparticles have found uses in magnetocaloric refrigeration, 4 neutron-capture therapy, 5 temperature sensing 6 and MRI. 7 Previous studies investigated the fabrication and characterization of thin films, 8 multilayers 9 and nanostructures [10][11][12][13] of Gd. In more recent work, 7 oxide-free Gd nanoparticles have been developed.…”

Section: Introductionmentioning

confidence: 99%

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Controlled nanocrystallinity in Gd nanobowls leads to magnetization of 226 emu/g

Ertaş

Bouchard

2017

Journal of Applied Physics

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Gadolinium (Gd) metal is of great interest in applications such as contrast-enhanced MRI and magnetic cooling. However, it is generally difficult to produce oxide-free and highly magnetic Gd nanoparticles due to the aggressively reactive nature of Gd with oxygen. Herein, we utilized a nanofabrication route and optimization of experimental conditions to produce highly magnetic air-stable oxide-free Gd nanoparticles. The nanobowls displayed the highest saturation magnetization to date for Gd, reaching 226.4 emu/g at 2 K. The crystalline composition of Gd is found to affect the observed magnetization values: the higher magnetization is observed for nanoparticles that have a lower content of the paramagnetic face-centered cubic (fcc) phase and a greater content of the ferromagnetic hexagonal close-packed (hcp) phase. The relative fcc content was found to depend on the deposition rate of the Gd metal during the nanofabrication process, thereby correlating with altered magnetization.

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Section: Resultsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Controlled nanocrystallinity in Gd nanobowls leads to magnetization of 226 emu/g

Ertaş

Bouchard

2017

Journal of Applied Physics

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“…Gadolinium oxide, being malleable and magnetic, is difficult to mill to nanoscale just simply by ball milling [41][42][43][44][45]. This work reports that an addition of inert NaCl can reduce the size of Gd2O3 by attrition and prevent the resulting refined particles from aggregation during the milling process [44].…”

Section: Introductionmentioning

confidence: 93%

A novel approach for the preparation of nanosized Gd2O3 structure: The influence of surface force on the morphology of ball milled particles

Leong

Watts

et al. 2016

Colloids and Surfaces A: Physicochemical and Engineering Aspect

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A novel approach for the preparation of nanosized Gd2O3 structure: the influence of surface force on the morphology of ball milled particles, Colloids and Surfaces A: Physicochemical and Engineering Aspects http://dx.(Yee-Kwong Leong) 2 GRAPHICAL ABSTRACT HIGHLIGHT  Without surfactants, milled Gd2O3 are rough (submicron) particles of various shapes.  High sodium dodecyl sulfate (SDS) adsorption on milled grains forms Gd2O3 nanowires.  Low cetyltrimethyl ammonium bromide (CTAB) adsorption forms coarser Gd2O3 particles. Surface force arising from surfactants adsorption varies the shape of milled Gd2O3. High SDS adsorbability stabilises the particles via steric and charge balance. ABSTRACTThis work investigates the effect of inter-particle forces arising from adsorbed typical cationic and anionic surfactants on the morphology of ball milled gadolinium oxide (Gd2O3). The experimental outcomes are interpreted in terms of stabilization and interaction mechanisms of fine washed Gd2O3 particles (size diameter <1 µm) in aqueous medium under the variation of surface forces arising of adsorbed surfactant. After ball milling and washing, the point of zero charge or isoelectric point (IEP) of Gd2O3 particles suspension is at pH 11 where its maximum yield stress is observed. Because of hydrophobic interaction, the maximum yield stress increases 3 by 30 times by adsorbed sodium dodecyl sulfate (SDS) and its IEP shifts slightly to a lower pH.By cetyl trimethyl ammonium bromide (CTAB), the yield stress also increases by a much smaller extent (3 times) and shifts to a higher pH of ~ 12.5. Without surfactants, the microstructure of dried Gd2O3 displays the coarse particles of various shapes, i.e. rod, spherical and cubic shapes. This indicates that the milled particles remain agglomerated in dispersion. In the presence of adsorbed anionic SDS, the particles are refined together with numerous 2D nanowire or nano-rod particles at pH ~ 8. In contrast, coarser particles with absence of nano-rods are found when cationic CTAB is used to modify the Gd2O3 surface at a pH of about 12.5. The SDS-modified suspension exhibits a much higher yield stress, which results from finer particles in suspension. This is invoked from organic shell formed by the high adsorbability of negatively charged heads of SDS into the bare positive charge density of the particle. The organic SDS shell prevents the fine particles from re-welding during the dispersing and annealing route. This work develops an inexpensive ball-milling approach with assisted SDS surfactant for mass production of nanosized Gd2O3 from bulky gadolinium material.

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“…Firstly, there is the influence of grain boundaries between DyRh crystals in the thin film on the magnetic ordering. RE metals are particularly sensitive to changes in interatomic spacing [32], hence crystalline material tends to suffer from reduced high-field magnetization for they often do not fully saturate [33] and, for Gd antiparallel coupling of adjacent atoms in the grain boundary region [34] was found to have negative impact, too. Secondly, there is a stressed lattice, which can have similar diminishing impact on magnetization due to a change in interatomic spacing, as for pure Dy [19].…”

Section: Magnetic Properties Of Dyrhmentioning

confidence: 99%

Ferromagnetism in DyRh and DyRhX (X = Fe, Ni, Co, Gd) thin films

Scheunert

Ambrose

Hendren³

et al. 2014

J. Phys. D: Appl. Phys.

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In an effort to achieve large high-field magnetization and increased Curie temperature, polycrystalline DyRh, (DyRh) 95 X 5 and (DyRh) 85 X 15 (X = Fe, Co, Ni, Gd) thin films have been prepared via ultra-high vacuum DC co-sputtering on SiO 2 and Si wafers, using Ta as seed and cap material. A body-centred cubic CsCl-like crystal formation (B2 phase) was achieved for DyRh around the equiatomic equilibrium, known from single crystals. The maximum in-plane spontaneous magnetization at T = 4K in fields of µ 0 H = 5T of was found to be µ 0 M S,4K = (1.50 ± 0.09)T with a ferromagnetic transition at T C = (5 ± 1)K and a coercivity of µ 0 H C,4K[D] = (0.010 ± 0.001)T (at T = 4K) for layers deposited on substrates heated to 350°C. Samples prepared at room temperature exhibited poorer texture, smaller grains and less B2-phase content; this did impact on the Curie temperature which was higher compared to those layers with best crystallisation; however the maximal magnetization stayed unaffected. Ferromagnetic coupling was observed in ternary alloys of DyRhGd and DyRhNi with an increased Curie temperature, larger initial permeability, and high-field magnetization which was best for (DyRh) 85 Gd 15 with µ 0 M S,4K[Gd15] = (2.10 ± 0.13)T.DyRhFe and DyRhCo showed antiparallel coupling of the spontaneous magnetic moments.

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Preparation, microstructure, and magnetic properties of bulk nanocrystalline Gd metal

Cited by 26 publications

References 10 publications

Controlled nanocrystallinity in Gd nanobowls leads to magnetization of 226 emu/g

Controlled nanocrystallinity in Gd nanobowls leads to magnetization of 226 emu/g

A novel approach for the preparation of nanosized Gd2O3 structure: The influence of surface force on the morphology of ball milled particles

Ferromagnetism in DyRh and DyRhX (X = Fe, Ni, Co, Gd) thin films

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