Simple and precise thermoelectric power measurement setup for different environments

Abstract

We report here on a simple but precise thermoelectric power measurement setup that can be adapted for different environments. This setup has been extensively used for cryogen-free environment to measure a variety of samples. It is made simple to load and hold the sample between two copper blocks by a spring-shaft arrangement. The usable range of measurements is a few microV/K to a few hundreds of microV/K. The salient features of the setup in achieving good precision both in natural warm-up/cooldown and controlled measurements are (i) the continuous DeltaT control across the sample by a chromel-AuFe(0.07%) thermocouple and (ii) the measurements of emf generated across the sample and the thermocouple using a nanovoltmeter and a scanner system. The versatile nature of the setup is further demonstrated by employing it in a magnetic field environment up to 140 kOe. The precision achieved using this system is highlighted for a few systems of current interest.

Enhancement in thermoelectric power of Ce(Ni1−xCux)2Al3: An implication of two‐band conduction

“…Phase purity was checked on unannealed powder specimens with a Bruker D8 Advanced X‐ray diffractometer using Cu Kα radiation. TEP measurements were done by the differential method (chromel/−Au + 0.07% Fe thermocouple as Δ T detector) using a homemade setup . Resistivity and heat‐capacity measurements were carried out using four‐probe and relaxation techniques, respectively, with the 14T/2K PPMS, (Quantum Design, USA) temperature down to 2 K and magnetic field up to 14 T.…”

Competing localization and quantum interference effects in Fe0.9Co0.1Si

“…Electrical resistivity measurements were carried out using a standard four‐point contact method down to 2 K and in fields up to 14 T using PPMS from M/S Quantum Design. Thermoelectric power measurements were performed using a homemade set up coupled to a 4 K closed cycle refrigerator using a dc differential method 15.…”

Temperature dependence of thermoelectric power and thermal conductivity in ferromagnetic shape memory alloyNi50Mn34In16Chandra1, Chattopadhyay2, Sharma3 et al. 2010Phys. Rev. BSelf Cite28030View full textAdd to dashboardCite

“…When temperature is further decreased in zero magnetic field, a sharp jump of about ϳ5 V / K is observed at the martensitic transition at about 240 K having a width of 1 K. It is observed that the jump in S across the first order structural transition is common in many of the systems such as NiTi, 34 Ce 3 Al, 35 Gd 5 Ge 4 , and related alloys, [36][37][38][39] and Ni 50−x Mn 25+x Ga 25 , 15 etc. It is also observed that the width of the jump is over several Kelvin for the case of non magnetic systems like NiTi and Ce 3 Al etc.…”

“…For the cooling cycle, the jump in the absolute thermopower across the structural transition can be from a lower value to a higher value, 15,34 or from a higher value to a lower value. [35][36][37][38][39][40] This can be understood by considering the changes in the electronic structure at the Fermi level across the martensitic transition. It is to be noted here that the overall electronic structure do not change much across the martensitic transition, but the Fermi level shifts either upwards or down wards.…”