For the characterization of novel quantum phases of matter, it is often required to study materials under multi-extreme conditions, in particular down to very low temperatures and in very high magnetic fields. We developed the world's smallest high-resolution capacitive dilatometer suitable for temperatures down to 10 mK and usage in high magnetic fields up to 37.5 T. Despite the extreme miniaturization, the capacitive dilatometer can resolve length changes down to 0.01 Å. This is an unprecedented resolution in a capacitive dilatometer of this compact size. Many cryogenic devices have limited space. Due to the extremely reduced cell size (3 cm, 12 g), implementation or new applications in many of these sample space lacking devices are now possible. As an important example, the minute device can now be rotated in any standard cryostat, including dilution refrigerators or the commercial physical property measurement system. The present super compact design provides also for high resolution thermal expansion and magnetostriction measurements in a 15.2 mm diameter tube, enabling its use in the 32 mm bore, 37.5 T Bitter magnet at the High Field Magnet Laboratory in Nijmegen down to a temperature of 300 mK.

CeIrSn with a quasikagome Ce lattice in the hexagonal basal plane is a strongly valence fluctuating compound, as we confirm by hard x-ray photoelectron spectroscopy and inelastic neutron scattering, with a high Kondo temperature of T K ∼ 480 K. We report a negative in-plane thermal expansion α=T below 2 K, which passes through a broad minimum near 0.75 K. Volume and a-axis magnetostriction for Bka are markedly negative at low fields and change sign before a sharp metamagnetic anomaly at 6 T. These behaviors are unexpected for Ce-based intermediate valence systems, which should feature positive expansivity. Rather they point towards antiferromagnetic correlations at very low temperatures. This is supported by muon spin relaxation measurements down to 0.1 K, which provide microscopic evidence for a broad distribution of internal magnetic fields. Comparison with isostructural CeRhSn suggests that these antiferromagnetic correlations emerging at T ≪ T K result from geometrical frustration.

Within a very few years, InAs/GaSb superlattice technology has proven its suitability for high-performance infrared imaging detector arrays. At the Fraunhofer Institute for Applied Solid State Physics (IAF) and AIM InfrarotModule GmbH, efforts have been focused on developing mature fabrication technology for dual-color InAs/GaSb superlattice focal-plane arrays for simultaneous, colocated detection at 3 lm to 4 lm and 4 lm to 5 lm in the mid-wavelength infrared atmospheric transmission window. Integrated into a wide-field-of-view missile approach warning system for an airborne platform, a very low number of pixel outages and cluster defects is mandatory for bispectral detector arrays. Process refinements, intense root-cause analysis, and specific test methodologies employed at various stages during the process have proven to be the key for yield enhancements.

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We report thermal expansion and magnetostriction of the cubic non-Kramers system PrIr2Zn20 with a non-magnetic Γ3 ground state doublet. In previous experiments, antiferroquadrupolar order at TQ = 0.11 K and a Fermi liquid state around Bc ≈ 5 T for B [001], indicative of possible ferrohastatic order, were discovered. For magnetic fields B [001], the low temperature longitudinal and transverse thermal expansion and magnetostriction are highly anisotropic. The resulting volume strain is very small, indicating that the Pr valence remains nearly constant as a function of magnetic field. We conclude that the Fermi liquid state around Bc forms through a very little change in c-f hybridization. This result is in sharp contrast to Ce-and Yb-based Kramers Kondo lattices which show significantly larger volume strains due to the high sensitivity of the Kondo temperature to hydrostatic pressure.