Onset of room temperature ferromagnetism by plastic deformation in three paramagnetic pure metals

Cepeda-Jiménez, C.M.; Hernando, A.; Barandiarán, J.M.; Pérez‐Prado, M.T.

doi:10.1016/j.scriptamat.2016.03.002

Cited by 6 publications

(2 citation statements)

References 21 publications

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“…1,2 As the d 0 magnetism combining both semiconducting and ferromagnetic properties may provide a new way to design spintronic devices, it has attracted great attention recently. [3][4][5][6][7] Although there are numerous discussions on d 0 ferromagnetism, its mechanism is still unclear. For example, whether or not d 0 ferromagnetism can be ascribed to either anionic vacancies or metal vacancies is not certain.…”

Section: Introductionmentioning

confidence: 99%

Ferromagnetic behavior of non-stoichiometric ZnS microspheres with a nanoplate-netted surface

et al. 2017

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Undoped ZnS microspheres with a size of 4-5 mm were produced using a hydrothermal method with different ratios of Zn and S precursors. Structural and morphological measurements show that the sphalerite ZnS microspheres have a cavity surface self-assembled with nanoplates with a thickness of 20-30 nm. Experimentally measured magnetic hysteresis curves for the undoped ZnS microspheres clearly indicate ferromagnetic behavior at room temperature with a saturation magnetization M s ¼ 3.66 and 1.566 memu g À1 for an atomic ratio of Zn to S equal to 0.966 and 1.32, respectively. The calculations based on density functional theory within the generalized gradient approximation + Hubbard U (GGA + U) approach demonstrated that the ZnS (111) surface with Zn vacancies produces a ferromagnetic state with a magnetic moment per unit cell of 2.0 m B ; the defective ZnS (111) surface with mixed Zn and S vacancies has a reduced magnetic moment of 1.12 m B because of the structural reconstruction, while the defective ZnS (111) surface with only S vacancies is non-magnetic. The observed weak ferromagnetism for the ZnS microspheres can be ascribed to the Zn vacancies and the cavity surface; the latter results in a large number of unsaturated bonds for the S and Zn atoms at the interfacial and surface regions. These studies will be helpful for understanding the d 0 ferromagnetism. Fig. 3 The XPS spectra of samples #1 and #2 (a). The Zn 2p3/2 spectra with Gaussian fitting of samples #1 (b) and #3 (c). The S 2p3/2 spectra with Gaussian fitting of samples #1 (d) and #3 (e).This journal is

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Section: Introductionmentioning

confidence: 99%

Ferromagnetic behavior of non-stoichiometric ZnS microspheres with a nanoplate-netted surface

et al. 2017

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“…The Curie point is the temperature that is thermodynamically sufficient to disrupt dipole alignments causing a magnetic transition from ferromagnetism to paramagnetism. This transition results in a well-documented nonlinearity in the Ni thermal expansion coefficient (TEC) [19 -23]; although, the temperature at which metals are able to exhibit ferromagnetism is thought to be sensitive to the level of strain to which the material is subjected to [30], and correlation has also been observed between the sintering and Néel temperature [31].…”

Section: Introductionmentioning

confidence: 99%

Understanding the thermo-mechanical behaviour of solid oxide fuel cell anodes using synchrotron X-ray diffraction

Heenan

Robinson

et al. 2018

Solid State Ionics

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The formation of cermet materials via the addition of electrolyte ceramic to metal-based electrodes has become widely adopted in solid oxide fuel cell fabrication due to its benefits in maximizing triple-phase boundary densities, while mitigating bulk thermal expansion mismatch between electrode and electrolyte layers. This work improves thermo-mechanical understanding via examination of nickel-based anode materials using synchrotron X-ray diffraction; two cermet materials are studied: Ni-YSZ and Ni-GDC, with comparison to a ceramic-free Ni sample. Findings conclude that although the ceramic addition has minor effects on the cubic Ni structure within isothermal environments, stress induced by the different thermal properties within the cermet materials results in a shifted Ni thermal expansion peak on passing the Curie point. Moreover, extended cycling of the Ni-YSZ sample suggests that low-temperature operation (ca. 600 ℃) may require several thermal cycles, or extended dwell times, to alleviate residual Ni stresses, this has potential implications for SOFC design and operation strategies. Highlights  The effects of ceramic addition to the expansion of the cubic structure of Ni in isothermal environments are minor over a single thermal cycle.  Accelerated stress tests revealed that lower temperature operation, i.e. 600 ℃ rather than higher 1000 ℃, results in deformation of the lattice parameters at both, low and high temperatures, likely due to a combination of two mechanisms: shock-induced tensile stress and delayed relaxation hysteresis.  High and low temperature deformation has been found to be divergent resulting in a greater relative deformation in the cold lattice parameters.  The thermal expansion non-linearity on passing the Ni Curie temperature is not suppressed; however, it is shifted to a higher temperature, a temperature that is dependent upon the ceramic employed.

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Tuning the magnetic properties of pure hafnium by high pressure torsion

et al. 2017

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Onset of room temperature ferromagnetism by plastic deformation in three paramagnetic pure metals

Cited by 6 publications

References 21 publications

Ferromagnetic behavior of non-stoichiometric ZnS microspheres with a nanoplate-netted surface

Ferromagnetic behavior of non-stoichiometric ZnS microspheres with a nanoplate-netted surface

Understanding the thermo-mechanical behaviour of solid oxide fuel cell anodes using synchrotron X-ray diffraction

Tuning the magnetic properties of pure hafnium by high pressure torsion

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