A microcalorimeter for studying the magnetocaloric effect and the heat capacity in magnetic fields

Korolev, V. V.; Romanov, A. S.; Aref'ev, I. M.

doi:10.1134/s0036024406020385

Cited by 8 publications

(6 citation statements)

References 1 publication

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“…The measurements of MCE and specific heat capacity of water suspension of the manganese complex were made with the use of automatic microcalorimeter with isothermal cover. [8] The microcalorimetric cell with the isothermal cover was placed into the interpoles clearance of the electromagnet (60 mm) ( Figure 1). It allowed measurements of MCE and specific heat capacity values in magnetic fields from 0 to 0.7 T at temperatures 283÷315 K. Temperature changing was registered by the high accuracy voltmeter connected with a computer.…”

Section: Methodsmentioning

confidence: 99%

“…10 -5 ºС, errors in the measurements of MCE and of the specific heat capacity were ± 0.1% and ± 1%, respectively. (2,3,7,8,12,13,17,18-octaethylporphynato)chloromanganese(III) (Cl)MnOEP was synthesized by Adler method [10] and purified by chromatography on Al 2 O 3 . n max (KBr)/cm -…”

Section: Methodsmentioning

confidence: 99%

“…The magnetic field dependences of the thermodynamic parameters of solid particles, namely the specific heat capacity, enthalpy changing and changing the magnetic component of the molar heat capacity and entropy were determined. Well characterized (2,3,7,8,12,13,17,18-octaethylporphynato)chloromanganese(III) (Cl)MnOEP was chosen as an object.…”

Section: Introductionmentioning

confidence: 99%

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Regularities of Magnetocaloric Effect and Determination of Some Thermodynamic Parameters for (Octaethylporphynato)chloro-manganese(III)

Korolev¹,

Klyueva²,

Arefyev³

et al. 2008

MHC

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chloromanganese(III) (6% suspension in water) were measured by microcalorimetric method in the dependence of temperature (298-353 K) and magnetic field (0-0.7 T). It is found that the MCE has positive value which increases with growth of the magnetic field induction at all the temperatures and decreases with the temperature growth at all the magnetic fields. Breaking the magnetic field leads to adiabatic demagnetizing. The dependence of specific heat capacity of the studied system from the value of magnetic field induction has maximum at 0.2-0.3 T at all the temperatures. When the induction value is higher than 0.6 T the specific heat capacity value is less than that in zero field. The temperature growth leads to the increase of the specific heat capacity in all the magnetic fields. On the base of the experimental data on the magnetocaloric effect and specific heat capacity of the manganese complex the dependencies of enthalpy, of the magnetic components of molar heat capacity and entropy from the temperature and magnetic induction are calculated.

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Section: Methodsmentioning

confidence: 99%

Section: Methodsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Regularities of Magnetocaloric Effect and Determination of Some Thermodynamic Parameters for (Octaethylporphynato)chloro-manganese(III)

Korolev¹,

Klyueva²,

Arefyev³

et al. 2008

MHC

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“…Studies of magnetocaloric effects (MCE), which are changes in the temperature of a magnetic material in external magnetic fields [1], are of great importance for solving fundamental magnetism and solid state physics problems. Interest in MCE is related to the possibility of obtaining information about the nature of the magneti cally ordered state.…”

Section: Introductionmentioning

confidence: 99%

The magnetothermal properties of substituted (tetraazoporphynato)manganese(III) in aqueous suspension

Korolev

Aref'ev

Ломова

et al. 2012

Russ. J. Phys. Chem.

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The magnetocaloric effect (MCE), heat capacity, and enthalpy and entropy of magnetization of the high spin (acetato) (2,3,7,8,12,13,17,18 octa para tert butylphenyltetraazaporphynato)manganese(III) complex in a 6% aqueous suspension were determined microcalorimetrically at 298 K in magnetic fields of 0.1-1.0 T, that is, under the conditions comparable with those used with (2,3,7,8,12,13,17,18 octaethylpor phynato)chloromagnanese(III) studied earlier. High dispersity complex particles were found to have para magnetic properties. Positive MCE values were obtained. These values grew as magnetic field induction increased. MCE sensitivity to the nature and electronic structure of the aromatic macroring was studied. The presence of aza groups in the structure of the complex decreases the MCE value compared with the porphyrin complex. The specific heat capacity of the complex strongly depended on the magnetic field value; field dependences had a maximum close to 0.3 T. Changes in the ΔS m (H, T) molar entropy part were also extremal and had maxima at 0.3-0.4 T. Prospects for the use of magnetothermal properties in the quantitative deter mination of thermodynamic characteristics and for revealing trends of changes in the magnetic activity of porphyrin complexes are discussed.

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“…One other example may be observed in Korolev (2005), although this system has been specifically designed to measure magnetic colloids. Instead of using a permanent magnet it is designed as a microcalorimetry cell placed between the two poles of an electromagnet so as to generate a (low intensity) magnetic field.…”

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confidence: 99%

Description of a differential setup for relaxation microcalorimetry

Leitão

Dommelen

Naastepad

et al. 2014

International Journal of Refrigeration

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A specific heat measuring instrument, with the capacity for the application of magnetic fields up to 9Tesla, resorting to microcalorimetry chips from the company Xensor Integration, has been successfully assembled and its functioning specifications are reported in the current paper. With this instrument is it possible to perform specific heat measurements with applied magnetic fields up to 9 Tesla in milligram samples. This offers our group the possibility to calculate the actual adiabatic temperature change of a material, as well as providing reliable and precise information on any phase transition that may be influenced by the application of a magnetic field.

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A microcalorimeter for studying the magnetocaloric effect and the heat capacity in magnetic fields

Cited by 8 publications

References 1 publication

Regularities of Magnetocaloric Effect and Determination of Some Thermodynamic Parameters for (Octaethylporphynato)chloro-manganese(III)

Regularities of Magnetocaloric Effect and Determination of Some Thermodynamic Parameters for (Octaethylporphynato)chloro-manganese(III)

The magnetothermal properties of substituted (tetraazoporphynato)manganese(III) in aqueous suspension

Description of a differential setup for relaxation microcalorimetry

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