Low-temperature electronics operating in below zero temperatures or even below the lower limit of the common −65 to 125 °C temperature range are essential in medical diagnostics, in space exploration and aviation, in processing and storage of food and mainly in scientific research, like superconducting materials engineering and their applications—superconducting magnets, superconducting energy storage, and magnetic levitation systems. Such electronic devices demand special approach to the materials used in passive elements and sensors. The main goal of this work was the implementation of a fully transparent, flexible cryogenic temperature sensor with graphene structures as sensing element. Electrodes were made of transparent ITO (Indium Tin Oxide) or ITO/Ag/ITO conductive layers by laser ablation and finally encapsulated in a polymer coating. A helium closed-cycle cryostat has been used in measurements of the electrical properties of these graphene-based temperature sensors under cryogenic conditions. The sensors were repeatedly cooled from room temperature to cryogenic temperature. Graphene structures were characterized using Raman spectroscopy. The observation of the resistance changes as a function of temperature indicates the potential use of graphene layers in the construction of temperature sensors. The temperature characteristics of the analyzed graphene sensors exhibit no clear anomalies or strong non-linearity in the entire studied temperature range (as compared to the typical carbon sensor).

The electrical properties of highly conductive ITO/Ag/ITO multilayer film at cryogenic temperatures have been presented in the paper for the first time. A good electrical conductivity and high thermal resistance of ITO/Ag/ITO are desirable features at cryogenic temperatures. Elements in ITO/Ag/ITO (AgHT™) were patterned using fiber laser ablation. Close to a linear (R2 = 0.999) relationship between resistance and temperature in the range of 293–55 K was confirmed. The dynamics of resistance changes is of the order of 9 × 10−4 1/K. Carrier concentration and mobility have been determined on the basis of Hall voltage measurements. Structures patterned in AgHT™ conductive film can be seen to be suitable for passive elements of low‐temperature electronics.

The paper presents magnetic parameters of LaFexCoySi1.1 bulk specimens proving strong magnetocaloric eect. The main research work was oriented on measurements of the alloy's power losses according to IEC 60404 standards and validated with unbalanced bridge method and other methods. The measurements of the LaFe10.8Co1.1Si1.1 specimens were determined in the range of temperatures near the Curie temperature where the magnetocaloric eect is the strongest. Power losses were taken into account mainly for the evaluation of usefulness and eciency in the magnetic refrigeration applications. The results of presented measurements testify that the most suitable range of temperature and the best operational conditions are very close to the point of magnetic phase transition and slightly above it. It indicates that the magnetic state between the T∆Smax and Tc is more eective for the magnetic refrigeration applications due to lower power losses and high level of the isothermal changes of entropy. Operating temperature below the T∆Smax in ferromagnetic state is improper because of the increasing power losses which achieve the level of 130 mJ/kg for main frequency and decrease to 20 mJ/kg for the value of 0.1 Hz.

Microjoining technologies are crucial for producing reliable electrical connections in modern microelectronic and optoelectronic devices, as well as for the assembly of electronic circuits, sensors, and batteries. However, the production of miniature sensors presents particular difficulties, due to their non-standard designs, unique functionality and applications in various environments. One of the main challenges relates to the fact that common methods such as reflow soldering or wave soldering cannot be applied to making joints to the materials used for the sensing layers (oxides, polymers, graphene, metallic layers) or to the thin metallic layers that act as contact pads. This problem applies especially to sensors designed to work at cryogenic temperatures. In this paper, we demonstrate a new method for the dynamic soldering of outer leads in the form of metallic strips made from thin metallic layers on ceramic substrates. These leads can be used as contact pads in sensors working in a wide temperature range. The joints produced using our method show excellent electrical, thermal, and mechanical properties in the temperature range of 15–300 K.

The article presents the results of dynamic tests of the most popular temperature sensors at low temperatures. The resistance sensors (Pt100) and thermocouples (type E and T) were tested. Measurements were carried out in the vacuum cryostat cooled by the closed cycle helium crycooler. The analysis of the temperature characteristics of sensors, the sensitivity and the influence of external factors on the measurement were presented in the paper. Streszczenie. W artykule przedstawiono wyniki badań dynamicznych najbardziej popularnych czujników temperatury w warunkach kriogenicznych. Badaniom zostały poddane czujniki rezystancyjne (Pt100) oraz czujniki termoelektryczne (typ E i T). Pomiary zostały zrealizowane w kriostacie próżniowym współpracującym z kriochłodziarką helową. Przedstawiono analizę charakterystyk temperaturowych czujników, ich czułości oraz wpływ czynników zewnętrznych na pomiar. Właściwości dynamiczne czujników temperatury w warunkach kriogenicznych.