Effect of copious vacancies on magnetims of Pd

Takano, Noriyuki; Kai, Tadashi; Shiiki, Kazuo; Terasaki, Fukunaga

doi:10.1016/0038-1098(95)00596-x

Cited by 24 publications

(16 citation statements)

References 14 publications

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“…1,2 Bulk palladium ͑fcc structure͒ presents a high paramagnetic susceptibility value, and it is close to fulfilling the Stoner criterion of magnetism, N͑E F ͒I Ͼ 1, where N͑E F ͒ is the density of states just below the Fermi level ͑E F ͒, and I stands for the Stoner parameter ͑typically 0.71 eV for Pd͒. 3 Accordingly, the factors that can affect the onset of ferromagnetism in Pd are those increasing N͑E F ͒ in order to accomplish the Stoner criterion. 4 Experiments carried out by Taniyama et al 4 have evidenced the appearance of magnetic moment in Pd clusters with average radius below 7 nm.…”

Section: Introductionmentioning

confidence: 88%

Magnetic and microstructural analysis of palladium nanoparticles with different capping systems

et al. 2006

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Palladium nanoparticles capped with different protective systems in a size range between 1.2 and 2.4 nm have been obtained by varying the preparation chemical method. Magnetization curves for all the samples show hysteresis loops, evidencing a ferromagnetic or a permanent magnetism in the nanoparticles. The microstructure of the nanoparticles has been analyzed by x-ray absorption and transmission electron microscopy. The nature of the magnetic behavior found for all these Pd nanoparticles ͑NPs͒ is different depending on their sizes and structural features and is explained on the basis of two different suggested mechanisms. The particles protected by means of a surfactant ͑tetralkylammonium salts͒, present a ferromagnetic order related to the factors increasing the density of states just below the Fermi level. Whereas, when the nanoparticles are stabilized by covalent bonds with protective species ͑thiol derivatized alkane chains or surface oxidized Pd NPs͒, the increase of the 4d density of holes, localized by the bonded atoms ͑S or O͒, is giving rise to the observed ferromagneticlike behavior.

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Section: Introductionmentioning

confidence: 88%

Magnetic and microstructural analysis of palladium nanoparticles with different capping systems

et al. 2006

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“…However, in bulk Pd no spontaneous ferromagnetic order has been observed. Although the density of states, N E , shows a sharp peak [N E F 1:23 states eV ÿ1 spin ÿ1 atom ÿ1 ] [1] just below the Fermi level E F , the Stoner criterion for ferromagnetism, N E F I > 1, is not satisfied (I stands for the Stoner parameter typically 0.71 eV for Pd) [1]. Nevertheless, Pd lies close to a ferromagnetic instability.…”

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confidence: 99%

“…The factors that can affect the onset of ferromagnetism are those increasing N E F : i.e., (i) confinement effects associated with a reduced coordination number that have been studied by analyzing thin layers [2] and clusters formed by a few atoms, (ii) local symmetry changes analyzed by observing the effect of vacancies [1] or by increasing the percentage of atoms at the grain boundaries or interfaces, and (iii) lattice expansion that induces a narrowing of the d band that according to theoretical calculations should be of the order of 5.3% for the onset of ferromagnetism [3].…”

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confidence: 99%

Ferromagnetism in fcc Twinned 2.4 nm Size Pd Nanoparticles

et al. 2003

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The onset of ferromagnetism has been experimentally observed in small Pd particles of average diameter 2.4 nm. High-resolution studies reveal that a high percentage of the fcc particle exhibits single and multiple twinning boundaries. The spontaneous magnetization close to 0:02 emu=g seems to indicate that only a small fraction of atoms holds a permanent magnetic moment and contributes to ferromagnetism. The possible origin of ferromagnetism is briefly discussed according to different models recently reported.

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“…34 Palladium, Pd, is a very good candidate for this kind of ME effect due to a very large paramagnetic DOS at the Fermi energy. 35,36 In recent years, a lot of efforts have been invested to explore the magnetism in Pd. Both the experiments and theory suggest that magnetism of Pd is very sensitive to the local atomic structure and surrounding environment.…”

Section: Introductionmentioning

confidence: 99%

Electrically driven magnetism on a Pd thin film

2010

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Using first-principles density-functional calculations, we demonstrate that ferromagnetism can be induced and modulated on an otherwise paramagnetic Pd metal thin-film surface through application of an external electric field. As free charges are either accumulated or depleted at the Pd surface to screen the applied electric field, there is a corresponding change in the surface density of states. This change can be made sufficient for the Fermi-level density of states to satisfy the Stoner criterion, driving a transition locally at the surface from a paramagnetic state to an itinerant ferromagnetic state above a critical applied electric field, E c . Furthermore, due to the second-order nature of this transition, the surface magnetization of the ferromagnetic state just above the transition exhibits a substantial dependence on electric field, as the result of an enhanced magnetoelectric susceptibility. Using a linearized Stoner model, we explain the occurrence of the itinerant ferromagnetism and demonstrate that the magnetic moment on the Pd surface follows a square-root variation with electric field, m ϰ ͑E − E c ͒ 1/2 , consistent with our first-principles calculations.

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Effect of copious vacancies on magnetims of Pd

Cited by 24 publications

References 14 publications

Magnetic and microstructural analysis of palladium nanoparticles with different capping systems

Magnetic and microstructural analysis of palladium nanoparticles with different capping systems

Ferromagnetism in fcc Twinned 2.4 nm Size Pd Nanoparticles

Electrically driven magnetism on a Pd thin film

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