Memory and rejuvenation in a quasicrystal

Joshi, D. C.; Gebresenbut, Girma Hailu; Gómez, Cesar Pay; Mathieu, Roland

doi:10.1209/0295-5075/132/27002

Cited by 8 publications

(3 citation statements)

References 29 publications

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Section: Resultsmentioning

confidence: 69%

“…The magnetic behavior of all the quasicrystalline Gd 1– x Eu x Cd 7.6±α samples was found to be similar to that of the binary i-GdCd 7.88 QC, showing a spin glass freezing at low temperatures. The results are summarized in Figures a and S10 for memory experiments on the QCs with x = 0.06 and 0.19. The freezing temperature T f is slightly lowered compared to that of the binary GdCd 7.88 QC, which differs from Y dilution in the Gd–Cd QC where the substitution of Gd with nonmagnetic Y atoms led to a more striking lowering of T f at similar doping concentrations.…”

Section: Resultsmentioning

confidence: 69%

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Eu Doping in the GdCd_7.88 Quasicrystal and Its Approximant Crystal GdCd₆

Denoel,

Huang,

Kondedan

et al. 2024

Inorg. Chem.

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The effect of Eu doping in the Tsai quasicrystal (QC) GdCd7.88 and its periodic 1/1 approximant crystal (AC) GdCd6 are investigated. This represents the first synthesis of Eu-containing stable QC samples, where three samples with the final composition Gd1–x Eu x Cd7.6±α at Eu doping concentrations x = 0.06, 0.13, and 0.19 are obtained (α ∼ 0.2). They are compared to two 1/1 ACs with compositions Gd1–x Eu x Cd6 (x = 0.12, 0.16). In addition, a new type of 1/1 AC, differing only by the inclusion of extra Cd sites unique to the Eu4Cd25 1/1 AC, has been discovered and synthesized for the concentrations Gd1–x Eu x Cd6+δ (x = 0.25, 0.33, 0.45, 0.69, 0.73, and 0 < δ ≤ 0.085). Due to the preferred cube morphology of its single grains, we refer to them as c-type 1/1 ACs and to the conventional standard ones as s-type. In both QCs and s-type ACs, the Eu content appears to saturate at a concentration of ∼20%. On the other hand, any Gd| Eu ratio is allowed in the c-type ACs, varying continuously between GdCd6 and Eu4Cd25. We describe and contrast the changes in composition, atomic structure, specific heat, and magnetic properties induced by Eu doping in the quasicrystalline phase and the s-type and c-type 1/1 ACs. By comparing our results to the literature data, we propose that the occupancy of the extra Cd sites can be used to predict the stability of Tsai-type quasicrystalline phases.

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Section: Resultsmentioning

confidence: 69%

Section: Resultsmentioning

confidence: 69%

Eu Doping in the GdCd_7.88 Quasicrystal and Its Approximant Crystal GdCd₆

Denoel,

Huang,

Kondedan

et al. 2024

Inorg. Chem.

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“…The ensembles of MNPs were measured between T = 2–300 K under an oscillating magnetic field amplitude of 0.313 mT and a frequency of . To probe memory effects and aging phenomena, several protocols can be found in the literature, including both static and dynamic susceptibility measurements 55 , 66 , 70 , 81 , 82 . In this work, we have recorded the out-of-phase component of the dynamic susceptibility, as it allows to detect in more detail the subtleties concerning the spin dynamics 55 , 70 .…”

Section: Methodsmentioning

confidence: 99%

Magnetic order and disorder environments in superantiferromagnetic $$\hbox {NdCu}_{\mathbf{2}}$$ nanoparticles

Jefremovas

Svedlindh

Damay

et al. 2022

Sci Rep

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Magnetic nanoparticles exhibit two different local symmetry environments, one ascribed to the core and one corresponding to the nanoparticle surface. This implies the existence of a dual spin dynamics, leading to the presence of two different magnetic arrangements governed by different correlation lengths. In this work, two ensembles of $$\hbox {NdCu}_{2}$$ NdCu 2 nanoparticles with mean sizes of 18 nm and 13 nm have been produced to unravel the magnetic couplings established among the magnetic moments located within the core and at the nanoparticle surface. To this end, we have combined neutron diffraction measurements, appropriate to investigate magnetically-ordered spin arrangements, with time-dependent macroscopic AC susceptibility measurements to reveal memory and aging effects. The observation of the latter phenomena are indicative of magnetically-frustrated states. The obtained results indicate that, while the $$\hbox {Nd}^{3{+}}$$ Nd 3 + magnetic moments located within the nanoparticle core keep the bulk antiferromagnetic commensurate structure in the whole magnetic state, the correlations among the surface spins give rise to a collective frustrated spin-glass phase. The interpretation of the magnetic structure of the nanoparticles is complemented by specific-heat measurements, which further support the lack of incommensurability in the nanoparticle state.

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Dual disorder-driven magnetic dynamics in GdCu2 superantiferromagnetic nanoparticles

2022

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The spin dynamics in magnetically disordered GdCu2 nanoparticles, varying the nanoparticle size in the range 53 to 7 nm, has been scrutinized. Dynamic χAC susceptibility measurements have revealed the existence of dissipation at Tg = 18 K, which is associated to the spin freezing transition, for all the ensembles. Besides, the superantiferromagnetic ensembles (〈D〉≥ 24 nm) also showcase a dissipation contribution close to the vicinity of the Néel transition, TN = 40.2 K. This dissipation, which takes the form of two humps located at Td1 = 33.5(5) K and Td2 = 40.0(5) K, is associated to uncompensated antiferromagnetic moments. Time-dependent phenomena (ageing and memory effects) are only evidenced below the spin freezing transition, evidencing that solely this low-temperature disordered phase is driven by the frustration of RKKY exchange interactions. Consequently, GdCu2 nanoparticles display a dual disorder-driven magnetic dynamics, which are the one ascribed to the magnetically frustrated moments located at the nanoparticle surface; and that of uncompensated antiferromagnetic moments located within the nanoparticle core.

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Memory and rejuvenation in a quasicrystal

Cited by 8 publications

References 29 publications

Eu Doping in the GdCd_7.88 Quasicrystal and Its Approximant Crystal GdCd₆

Eu Doping in the GdCd_7.88 Quasicrystal and Its Approximant Crystal GdCd₆

Magnetic order and disorder environments in superantiferromagnetic $$\hbox {NdCu}_{\mathbf{2}}$$ nanoparticles

Dual disorder-driven magnetic dynamics in GdCu2 superantiferromagnetic nanoparticles

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Memory and rejuvenation in a quasicrystal

Cited by 8 publications

References 29 publications

Eu Doping in the GdCd7.88 Quasicrystal and Its Approximant Crystal GdCd6

Eu Doping in the GdCd7.88 Quasicrystal and Its Approximant Crystal GdCd6

Magnetic order and disorder environments in superantiferromagnetic $$\hbox {NdCu}_{\mathbf{2}}$$ nanoparticles

Dual disorder-driven magnetic dynamics in GdCu2 superantiferromagnetic nanoparticles

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Product

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Eu Doping in the GdCd_7.88 Quasicrystal and Its Approximant Crystal GdCd₆

Eu Doping in the GdCd_7.88 Quasicrystal and Its Approximant Crystal GdCd₆