Simultaneous measurement of specific heat and thermal conductivity in pulsed magnetic fields

Abstract

We report an experimental setup for simultaneously measuring specific heat and thermal conductivity in feedback-controlled pulsed magnetic fields of 50 ms duration at cryogenic temperatures. A stabilized magnetic field pulse obtained by the feedback control, which dramatically improves the thermal stability of the setup and sample, is used in combination with the flash method to obtain absolute values of thermal properties up to 37.2 T in the 22–16 K temperature range. We describe the experimental setup and demonstrate the performance of the present method with measurements on single-crystal samples of the geometrically frustrated quantum spin-dimer system SrCu2(BO3)2. Our proof-of-principle results show excellent agreement with data taken using a standard steady-state method, confirming the validity and convenience of the present approach.

An Inductive Method for Comprehensive Estimation of Temperature-Dependent Electrical and Thermal Properties of Conductive Ferromagnetic Materials

“…By analysing conductive non-magnetic materials [11], it was found that in the system in Figure 2a, it is possible to use the modified Flash method [12][13][14][15][16][17] to estimate the thermal diffusivity of a cylindrical sample of the tested material. The application of the Flash method in the considered inductor-charge system consisted of implementing, using the system from Figure 2c, excitation in the form of short 20 or 10 millisecond pulses of the inductor current with a frequency of f = 40 kHz and RSM values of I = 1100 and 1550A, respectively.…”

“…The rest of the article initially presents brief information about the measurement station and the simulation analysis methods used. The method of using the modified Flash method [12][13][14][15][16][17] for the measurement of thermal diffusivity at an induction heating measurement station was presented, and the possibilities of measuring the volumetric heat capacity of ferromagnetic materials using the same measurement station were analysed. The influence of resistivity and magnetic permeability on the tested electrical parameters of the measurement system is discussed, and the possibilities of distinguishing the influence of each of these properties individually are indicated.…”

Method of Determining the Temperature Characteristics of the Thermal and Electrical Properties of Conductive Materials on a Stand for Induction Heating

“…Only the procedure of heating and measuring the temperature response of the charge was changed here. For the measurement of thermal diffusivity, use of the modified Flash method [10][11][12][13][14] was proposed.…”

“…Only the procedure of heating and measuring the temperature response of the charge was changed here. For the measurement of thermal diffusivity, use of the modified Flash method [10][11][12][13][14] was proposed. The classic Flash method consists of directing a pulse of electromagnetic radiation (from a radiator or a laser) of a character as close as possible to the Dirac pulse at the base of the cylindrical charge and recording, in the time domain, the temperature on the opposite side.…”

“…In this method, it is important that the level of energy supplied is sufficiently high and that it is uniformly distributed over the surface. In [9], unlike in other systems reported in the literature [10][11][12][13][14][15] (radiator or laser), a high-frequency generator powering the induction heating system (IHS) shown in Figure 1 was used as the source of the electromagnetic pulse. This led to a disturbance in the uniform power dissipation on the surface of the tested material sample; thus, the influence of the location of the temperature response measurement point on the duration of the pulse and on determined the thermal diffusivity of the tested material.…”