Experiment on Nuclear Ordering and Superconductivity in Lithium

Juntunen, Kirsi; Tuoriniemi, Juha

doi:10.1007/s10909-005-8539-z

Cited by 6 publications

(6 citation statements)

References 61 publications

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“…24 or 0.06 ͑K s͒ −1 of more recent work in Ref. 25. In the case of Na, our theoretical estimate is ͑1/T 1 T͒ F-c Ϸ 0.213 ͑K s͒ −1 , while the experimental value from Ref.…”

Section: A Alkaline Metalsmentioning

confidence: 39%

Divergence of the orbital nuclear magnetic relaxation rate in metals

2007

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We analyze the nuclear magnetic relaxation rate $(1/T_1)_{orb}$ due to the coupling of nuclear spin to the orbital moment of itinerant electrons in metals. In the clean non--interacting case, contributions from large--distance current fluctuations add up to cause a divergence of $(1/T_1)_{orb}$. When impurity scattering is present, the elastic mean free time $\tau$ cuts off the divergence, and the magnitude of the effect at low temperatures is controlled by the parameter $\ln(\mu \tau)$, where $\mu$ is the chemical potential. The spin--dipolar hyperfine coupling, while has the same spatial variation $1/r^3$ as the orbital hyperfine coupling, does not produce a divergence in the nuclear magnetic relaxation rate.Comment: 11pages; v4: The analysis of the normal state is more compelete now, including a comparison with other hyperfine interactions and a detailed discussion of the effect in representative metals. The superconducting state is excluded from consideration in this pape

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“…24 or 0.06 ͑K s͒ −1 of more recent work in Ref. 25. In the case of Na, our theoretical estimate is ͑1/T 1 T͒ F-c Ϸ 0.213 ͑K s͒ −1 , while the experimental value from Ref.…”

Section: A Alkaline Metalsmentioning

confidence: 39%

Divergence of the orbital nuclear magnetic relaxation rate in metals

2007

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“…As this pattern is far more complex than expected, we initially thought this peculiar response not indicating superconductivity down to 0.1 mK, as reported in Refs. [17] and [18]. However, in view of the further results on similar samples, as discussed above, this conclusion must be revised.…”

mentioning

confidence: 84%

“…competition between these two ordering phenomena under suitably prepared conditions. 17,18 The Fermi gas of conduction electrons in any metal is forced to a state with high energy content, of the order of thousands of kelvins, due to the Pauli exclusion principle. The degenerate state is susceptible to symmetry breaking phase transitions lowering the ground state energy due to even weak interactions between the electrons.…”

mentioning

confidence: 99%

Superconductivity in lithium below 0.4 millikelvin at ambient pressure

Tuoriniemi¹,

Juntunen-Nurmilaukas

Uusvuori³

et al. 2007

Nature

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Elements in the alkali metal series are regarded as unfavourable for superconductivity due to their monovalent character. 1,2 The superconducting transition at temperatures as high as 20 K recently found in compressed lithium, 3-6 the lightest alkali element, is considered to occur due to pressure induced changes in the conduction-electron band structure. 6-12 The condition at the ambient pressure in lithium had remained unresolved, both theoretically and experimentally. 11-16 Here we report that lithium is a superconductor also at zero pressure at extremely low temperatures below 0.4 mK. This is the lowest superconducting transition temperature for any pure metal ever observed. Lithium, as a particularly simple host for the conduction electron system, represents an important case for any attempts to classify the superconductors and transition temperatures, especially in judging if any nonmagnetic configuration can be assumed to exclude superconductivity down to zero temperature. Such a fundamental system provides a stringent test case for already highly developed computational methods in predicting the transition temperatures from first principles. Furthermore, the combination of extremely weak superconductivity and relatively strong nuclear magnetism in lithium would evidently lead to mutual

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“…For this reason, critical temperatures for nuclear spin ordering in metals or insulators are generally less than 1 μK [6], except for Van Vleck paramagnets [7] and solid He 3 [8], where they are in the mK range. Nevertheless, since nuclear spin systems (NSSs) offer a rich playground in the field of magnetism, they have motivated a large body of research [6,7,[9][10][11][12][13][14][15][16][17][18][19]. Because a NSS reaches an internal equilibrium within a time T 2 , much shorter than the spin-lattice relaxation time T 2 T 1 , nuclear spins can be cooled down to temperatures much lower than the lattice temperature [20][21][22].…”

Section: Introductionmentioning

confidence: 99%

Electron-induced nuclear magnetic ordering in n -type semiconductors

et al. 2021

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Nuclear magnetism in n-doped semiconductors with a positive hyperfine constant is revisited. Two kinds of nuclear magnetic ordering can be induced by resident electrons in a deeply cooled nuclear spin system. At positive nuclear spin temperature below a critical value, randomly oriented nuclear spin polarons similar to that predicted by Merkulov [Phys. Solid State 40, 930 (1998)] should emerge. These polarons are oriented randomly, and within each polaron, nuclear and electron spins are aligned antiferromagnetically. At negative nuclear spin temperature below a critical value, we predict another type of magnetic ordering-a dynamically induced nuclear ferromagnet. This is a long-range ferromagnetically ordered state involving both electrons and nuclei. It can form if electron spin relaxation is dominated by the hyperfine coupling, rather than by the spin-orbit interaction. Application of the theory to the n-doped GaAs suggests that ferromagnetic order may be reached at experimentally achievable nuclear spin temperature N ≈ −0.5 μK and lattice temperature T L ≈ 5 K.

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Experiment on Nuclear Ordering and Superconductivity in Lithium

Cited by 6 publications

References 61 publications

Divergence of the orbital nuclear magnetic relaxation rate in metals

Divergence of the orbital nuclear magnetic relaxation rate in metals

Superconductivity in lithium below 0.4 millikelvin at ambient pressure

Electron-induced nuclear magnetic ordering in n -type semiconductors

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