Precise Calorimetry of Small Metal Samples Using Noise Thermometry

Fuente: arXiv
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Main Authors: Knapp, Jan, Levitin, Lev V., Nyéki, Ján, Brando, Manuel, Saunders, John
Format: Preprint
Published: 2024
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author Knapp, Jan
Levitin, Lev V.
Nyéki, Ján
Brando, Manuel
Saunders, John
author_facet Knapp, Jan
Levitin, Lev V.
Nyéki, Ján
Brando, Manuel
Saunders, John
contents We describe a compact calorimeter that opens ultra-low temperature heat capacity studies of small metal crystals in moderate magnetic fields. The performance is demonstrated on the canonical heavy Fermion metal YbRh2Si2. Thermometry is provided by a fast current sensing noise thermometer. This single thermometer enables us to cover a wide temperature range of interest from 175 $μ$K to 90 mK with temperature independent relative precision. Temperatures are tied to the international temperature scale with a single point calibration. A superconducting solenoid surrounding the cell provides the sample field for tuning its properties and operates a superconducting heat switch. Both adiabatic and relaxation calorimetry techniques, as well as magnetic field sweeps, are employed. The design of the calorimeter results in an addendum heat capacity which is negligible for the study reported. The keys to sample and thermometer thermalisation are the lack of dissipation in the temperature measurement and the steps taken to reduce the parasitic heat leak into the cell to the tens of fW level.
format Preprint
id arxiv_https___arxiv_org_abs_2407_01434
institution arXiv
publishDate 2024
record_format arxiv
spellingShingle Precise Calorimetry of Small Metal Samples Using Noise Thermometry
Knapp, Jan
Levitin, Lev V.
Nyéki, Ján
Brando, Manuel
Saunders, John
Instrumentation and Detectors
We describe a compact calorimeter that opens ultra-low temperature heat capacity studies of small metal crystals in moderate magnetic fields. The performance is demonstrated on the canonical heavy Fermion metal YbRh2Si2. Thermometry is provided by a fast current sensing noise thermometer. This single thermometer enables us to cover a wide temperature range of interest from 175 $μ$K to 90 mK with temperature independent relative precision. Temperatures are tied to the international temperature scale with a single point calibration. A superconducting solenoid surrounding the cell provides the sample field for tuning its properties and operates a superconducting heat switch. Both adiabatic and relaxation calorimetry techniques, as well as magnetic field sweeps, are employed. The design of the calorimeter results in an addendum heat capacity which is negligible for the study reported. The keys to sample and thermometer thermalisation are the lack of dissipation in the temperature measurement and the steps taken to reduce the parasitic heat leak into the cell to the tens of fW level.
title Precise Calorimetry of Small Metal Samples Using Noise Thermometry
topic Instrumentation and Detectors
url https://arxiv.org/abs/2407.01434