Stress-induced large Curie temperature enhancement in<mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline"><mml:mrow><mml:msub><mml:mrow><mml:mtext>Fe</mml:mtext></mml:mrow><mml:mrow><mml:mn>64</mml:mn></mml:mrow></mml:msub><mml:msub><mml:mrow><mml:mtext>Ni</mml:mtext></mml:mrow><mml:mrow><mml:mn>36</mml:mn></mml:mrow></mml:msub></mml:mrow></mml:math>Invar alloy

Gorría, P.; Martínez-Blanco, David; Pérez, M.J.; Blanco, J.A.; Hernando, A.; Laguna-Marco, M. A.; Haskel, D.; Souza-Neto, N. M.; Smith, Ronald I.; Marshall, William G.; Garbarino, Gastón; Mézouar, M.; Fernández-Martı́nez, Alejandro; Chaboy, J.; Barquı́n, L. Fernández; Castrillón, J. A. Rodríguez; Moldován, Mariella; Alonso, J. Ignacio García; Zhang, Jianzhong; Llobet, Anna; Jiang, J. S.

doi:10.1103/physrevb.80.064421

Cited by 66 publications

(28 citation statements)

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“…For T ∼ T C , the magnetization at H = 80 kOe is close to the value of the isotherm at T = 2 K, which indicates that the magnetic field is able to increase the magnetization due to magnetovolume effects like in other well-known Fe invar alloys. 25,59 For T = 390 K, the magnetization at H = 80 kOe is ∼60% of the magnetization at T = 160 K.…”

Section: A Magnetic Properties Of Er 2 Fe 17mentioning

confidence: 99%

“…Further heating shows another region of NTE with a minimum value for the volume at T ∼ 320 K. These anomalies in the unit cell volume were ascribed to the strong dependence of magnetic coupling with the Fe-Fe distances, 22,25,40,69 likewise many other Fe-based Invar alloys either in amorphous or crystalline state. 59,[70][71][72] At low temperatures, the unit cell volume is expanded respect to a nonmagnetic system [see Fig. 6(b), where both the experimental and the nonmagnetic cell volumes are plotted].…”

Section: Magnetovolume Anomalies Of Er 2 Fe 17mentioning

confidence: 99%

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Magnetovolume and magnetocaloric effects in Er2Fe17

et al. 2012

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Combining different experimental techniques, investigations in hexagonal P 6 3 /mmc Er 2 Fe 17 show remarkable magnetovolume anomalies below the Curie temperature, T C . The spontaneous magnetostriction reaches 1.6 × 10 −2 at 5 K and falls to zero well above T C , owing to short-range magnetic correlations. Moreover, Er 2 Fe 17 exhibits direct and inverse magnetocaloric effects (MCE) with moderate isothermal magnetic entropy S M , and adiabatic temperature T ad changes [ S M ∼ −4.7 J(kgK) −1 and T ad ∼ 2.5 K near the T C , and S M ∼ 1.3 J(kgK)and T ad ∼ −0.6 K at 40 K for H = 80 kOe, respectively, determined from magnetization measurements].The existence of an inverse MCE seems to be related to a crystalline electric field-level crossover in the Er sublattice and the ferrimagnetic arrangement between the magnetic moments of the Er and Fe sublattice. The main trends found experimentally for the temperature dependence of S M and T ad as well as for the atomic magnetic moments are qualitatively well described considering a mean-field Hamiltonian that incorporates both crystalline electric field and exchange interactions. S M (T ) and T ad (T ) curves are essentially zero at ∼150 K, the temperature where the transition from direct to inverse MCE occurs. A possible interplay between the MCE and the magnetovolume anomalies is also discussed.

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Section: A Magnetic Properties Of Er 2 Fe 17mentioning

confidence: 99%

Section: Magnetovolume Anomalies Of Er 2 Fe 17mentioning

confidence: 99%

Magnetovolume and magnetocaloric effects in Er2Fe17

et al. 2012

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“…43 These results clearly indicate that milled powders exhibit high T C as compared to the NiO nanoparticles prepared by sol-gel method. This could be due to the high stress induced during the ball milling process 44,45 or strain due to lattice mismatch between Ni and NiO arising at the interface 42 and possible competing exchange interaction between the induced FM and AFM core. The presence of such strains acts more like hydrostatic one, which is expected to increase T C as reported in bulk Ni.…”

Section: -9mentioning

confidence: 99%

Enhanced room temperature ferromagnetism in antiferromagnetic NiO nanoparticles

2015

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We report systematic investigations of structural, vibrational, resonance and magnetic properties of nanoscale NiO powders prepared by ball milling process under different milling speeds for 30 hours of milling. Structural properties revealed that both pure NiO and as-milled NiO powders exhibit face centered cubic structure, but average crystallite size decreases to around 11 nm along with significant increase in strain with increasing milling speed. Vibrational properties show the enhancement in the intensity of one-phonon longitudinal optical (LO) band and disappearance of two-magnon band due to size reduction. In addition, two-phonon LO band exhibits red shift due to size-induced phonon confinement effect and surface relaxation. Pure NiO powder exhibit antiferromagnetic nature, which transforms into induced ferromagnetic after size reduction. The average magnetization at room temperature increases with decreasing the crystallite size and a maximum moment of 0.016 μB/f.u. at 12 kOe applied field and coercivity of 170 Oe were obtained for 30 hours milled NiO powders at 600 rotation per minute milling speed. The change in the magnetic properties is also supported by the vibrational properties. Thermomagnetization measurements at high temperature reveal a well-defined magnetic phase transition at high temperature (TC) around 780 K due to induced ferromagnetic phase. Electron paramagnetic resonance (EPR) studies reveal a good agreement between the EPR results and magnetic properties. The observed results are described on the basis of crystallite size variation, defect density, large strain, oxidation/reduction of Ni and interaction between uncompensated surfaces and particle core with lattice expansion. The obtained results suggest that nanoscale NiO powders with high TC and moderate magnetic moment at room temperature with cubic structure would be useful to expedite for spintronic devices.

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“…HP XMCD has been well developed for studying HP effects on ferro(ferri)-magnetic materials, yielding element and orbital-selective magnetization [16,59,[228][229][230]. In particular, XMCD is advantageous in cases where more than one magnetic element is present.…”

Section: Hp X-ray Magnetic Circular Dichroismmentioning

confidence: 99%

High-pressure studies with x-rays using diamond anvil cells

2016

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Pressure profoundly alters all states of matter. The symbiotic development of ultrahighpressure diamond anvil cells, to compress samples to sustainable multi-megabar pressures; and synchrotron x-ray techniques, to probe materials' properties in situ, has enabled the exploration of rich high-pressure (HP) science. In this article, we first introduce the essential concept of diamond anvil cell technology, together with recent developments and its integration with other extreme environments. We then provide an overview of the latest developments in HP synchrotron techniques, their applications, and current problems, followed by a discussion of HP scientific studies using x-rays in the key multidisciplinary fields. These HP studies include: HP x-ray emission spectroscopy, which provides information on the filled electronic states of HP samples; HP x-ray Raman spectroscopy, which probes the HP chemical bonding changes of light elements; HP electronic inelastic x-ray scattering spectroscopy, which accesses high energy electronic phenomena, including electronic band structure, Fermi surface, excitons, plasmons, and their dispersions; HP resonant inelastic x-ray scattering spectroscopy, which probes shallow core excitations, multiplet structures, and spin-resolved electronic structure; HP nuclear resonant x-ray spectroscopy, which provides phonon densities of state and time-resolved Mössbauer information; HP x-ray imaging, which provides information on hierarchical structures, dynamic processes, and internal strains; HP x-ray diffraction, which determines the fundamental structures and densities of single-crystal, polycrystalline, nanocrystalline, and non-crystalline materials; and HP radial x-ray diffraction, which yields deviatoric, elastic and rheological information. Integrating these tools with hydrostatic or uniaxial pressure media, laser and resistive heating, and cryogenic cooling, has enabled investigations of the structural, vibrational, electronic, and magnetic properties of materials over a wide range of pressure-temperature conditions.

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Stress-induced large Curie temperature enhancement inFe64Ni36Invar alloy

Cited by 66 publications

References 50 publications

Magnetovolume and magnetocaloric effects in Er2Fe17

Magnetovolume and magnetocaloric effects in Er2Fe17

Enhanced room temperature ferromagnetism in antiferromagnetic NiO nanoparticles

High-pressure studies with x-rays using diamond anvil cells

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