Verification of Wiedemann-Franz law in silver with moderate residual resistivity ratio

Electrical and thermal transport were studied in a vacuum-annealed polycrystalline silver wire with residual resistivity ratio 200-400, in the temperature range 0.1-1.2K and in magnetic fields up to 5T. Both at zero field and at 5T the wire exhibits the Wiedemann-Franz law with the fundamental Lorenz number, contrary to an earlier report [Gloos, K. et al, Cryogenics 30, 14 (1990)]. Our result demonstrates that silver is an excellent material for thermal links in ultra-low-temperature experiments operating at high magnetic fields.Comment: 8 pages, 3 figure

High performance cryogen-free microkelvin platform

Improved accessibility to the microkelvin temperature regime is important for future research in quantum materials; for quantum information science; and for applications of quantum sensors. Here we report the design and performance of a microkelvin platform based on a nuclear demagnetization stage, engineered and well optimized for operation on a standard cryogen-free dilution refrigerator. PrNi5 is used as the dominant refrigerant. The platform provides a large area for mounting experiments in an ultralow temperature, low electromagnetic noise environment. The performance is characterized using current sensing noise thermometry. Temperatures as low as 395 $\mu$K have been reached, and a protocol has been established in which it is possible to operate experiments below 1 mK for 95% of the time, providing an efficient cryogen-free microkelvin environment for a wide range of science applicationsComment: 8 pages, 5 figure

Cooling low-dimensional electron systems into the microkelvin regime.

Two-dimensional electron gases (2DEGs) with high mobility, engineered in semiconductor heterostructures host a variety of ordered phases arising from strong correlations, which emerge at sufficiently low temperatures. The 2DEG can be further controlled by surface gates to create quasi-one dimensional systems, with potential spintronic applications. Here we address the long-standing challenge of cooling such electrons to below 1 mK, potentially important for identification of topological phases and spin correlated states. The 2DEG device was immersed in liquid 3He, cooled by the nuclear adiabatic demagnetization of copper. The temperature of the 2D electrons was inferred from the electronic noise in a gold wire, connected to the 2DEG by a metallic ohmic contact. With effective screening and filtering, we demonstrate a temperature of 0.9 ± 0.1 mK, with scope for significant further improvement. This platform is a key technological step, paving the way to observing new quantum phenomena, and developing new generations of nanoelectronic devices exploiting correlated electron states

Human Milk Banking-Facts and Issues to Resolve

The number of human milk banks is increasing worldwide. Although the beneficial effects of feeding premature infants with their mother’s milk are well documented, less is known about the effects of feeding these infants with pasteurized donor milk. We propose a randomized trial comparing the effects of a 100% human milk-based diet (human milk supplemented with a human milk-derived fortifier) and a diet (partially) based on bovine milk. In theory, human milk has a beneficial effect on various aspects of human physiology, most of which become apparent after infancy. We therefore propose an extensive follow-up program that takes this aspect into consideration. Other issues concerning the practice of human milk banks need to be addressed as well as optimization of the feeding strategies for preterm infants

Ultrasmall Moment Incommensurate Spin Density Wave Order Masking a Ferromagnetic Quantum Critical Point in NbFe₂

In the metallic magnet Nb1−yFe2þy, the low temperature threshold of ferromagnetism can be investigatedby varying the Fe excessywithin a narrow homogeneity range. We use elastic neutron scattering to trackthe evolution of magnetic order from Fe-rich, ferromagnetic Nb0.981Fe2.019to approximately stoichiometricNbFe2, in which we can, for the first time, characterize a long-wavelength spin density wave state burying aferromagnetic quantum critical point. The associated ordering wave vectorqSDW¼ð0;0;lSDWÞis found todepend significantly onyandT, staying finite but decreasing as the ferromagnetic state is approached. Thephase diagram follows a two-order-parameter Landau theory, for which all of the coefficients can now bedetermined. Our findings suggest that the emergence of spin density wave order cannot be attributed toband structure effects alone. They indicate a common microscopic origin of both types of magnetic orderand provide strong constraints on related theoretical scenarios based on, e.g., quantum order by disorder

Arabic and contact-induced change

This volume offers a synthesis of current expertise on contact-induced change in Arabic and its neighbours, with thirty chapters written by many of the leading experts on this topic. Its purpose is to showcase the current state of knowledge regarding the diverse outcomes of contacts between Arabic and other languages, in a format that is both accessible and useful to Arabists, historical linguists, and students of language contact

Arabic and contact-induced change

This volume offers a synthesis of current expertise on contact-induced change in Arabic and its neighbours, with thirty chapters written by many of the leading experts on this topic. Its purpose is to showcase the current state of knowledge regarding the diverse outcomes of contacts between Arabic and other languages, in a format that is both accessible and useful to Arabists, historical linguists, and students of language contact

Arabic and contact-induced change

This volume offers a synthesis of current expertise on contact-induced change in Arabic and its neighbours, with thirty chapters written by many of the leading experts on this topic. Its purpose is to showcase the current state of knowledge regarding the diverse outcomes of contacts between Arabic and other languages, in a format that is both accessible and useful to Arabists, historical linguists, and students of language contact