Nanocalorimeter platform for in situ specific heat measurements and x-ray diffraction at low temperature

Abstract

Recent advances in electronics and nanofabrication have enabled membrane-based nanocalorimetry for measurements of the specific heat of microgram-sized samples. We have integrated a nanocalorimeter platform into a 4.5 T split-pair vertical-field magnet to allow for the simultaneous measurement of the specific heat and x-ray scattering in magnetic fields and at temperatures as low as 4 K. This multi-modal approach empowers researchers to directly correlate scattering experiments with insights from thermodynamic properties including structural, electronic, orbital, and magnetic phase transitions. The use of a nanocalorimeter sample platform enables numerous technical advantages: precise measurement and control of the sample temperature, quantification of beam heating effects, fast and precise positioning of the sample in the x-ray beam, and fast acquisition of x-ray scans over a wide temperature range without the need for time-consuming re-centering and re-alignment. Furthermore, on an YBaCuO crystal and a copper foil, we demonstrate a novel approach to x-ray absorption spectroscopy by monitoring the change in sample temperature as a function of incident photon energy. Finally, we illustrate the new insights that can be gained from in situ structural and thermodynamic measurements by investigating the superheated state occurring at the first-order magneto-elastic phase transition of FeP, a material that is of interest for magnetocaloric applications.

Time-reversal invariant and fully gapped unconventional superconducting state in the bulk of the topological compound Nb0.25Bi2Se3

“…The magnetization measurements were performed in a commercial SQUID magnetometer (Quantum Design MPMS-XL). AC specific heat was measured on a SiN membrane-based nanocalorimeter platform [33]. The temperature dependence of the superconducting contribution [34] (the normal-state electronic specific heat is subtracted) was extracted by subtracting data with H ( c) = 1 T from the zero-field data [35].…”

Melting of vortex lattice in the magnetic superconductor RbEuFe4As4

“…[44]. For specific heat measurements, we mounted small (100µm×100µm×10µm), uncut, platelet-shaped single crystals onto a SiN membrane based nanocalorimeter platform [57,58] using Apiezon grease. The probe was then inserted into a three-axis vector magnet (1T-1T-9T), where we estimate the field to be aligned with the crystal axes up to ±3 degrees.…”

Strongly fluctuating moments in the high-temperature magnetic superconductor RbEuFe4As4

“…For our calorimetry experiment, we mounted a small, platelet-shaped RbEuFe 4 As 4 single crystal, grown in RbAs flux 44 , onto a nanocalorimeter platform 45,46 using Apiezon grease, see Fig. 1.…”