Fluorine-bridged rare earth molecular cluster magnetic refrigeration material and preparation method thereof

A magnetic refrigeration material and molecular cluster technology, applied in the field of material science, can solve the problems of poor magnetic refrigeration performance and achieve good thermal stability, high yield and good effect

Active Publication Date: 2021-07-23
西安交通大学深圳研究院 +1
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  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

[0007] The purpose of the present invention is to provide a fluorine-bridged rare earth molecular cluster magnetic refrigeration material and its preparation method to overcome the problem of poor magnetic refrigeration performance of existing gadolinium-based cluster materials at low field. The rare earth molecular cluster magnetic refrigeration material has good thermal stability and solution stability, and has a large magnetic entropy change in the low temperature region

Method used

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  • Fluorine-bridged rare earth molecular cluster magnetic refrigeration material and preparation method thereof
  • Fluorine-bridged rare earth molecular cluster magnetic refrigeration material and preparation method thereof
  • Fluorine-bridged rare earth molecular cluster magnetic refrigeration material and preparation method thereof

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preparation example Construction

[0036] A preparation method of a fluorine-bridged rare earth molecular cluster magnetic refrigeration material, comprising the following steps:

[0037] Step 1), uniformly dispersing the rare earth metal source in an organic solvent, and then adding a fluorine source to the organic solvent dispersed with the rare earth metal to obtain a reaction system A;

[0038] In step 2), the reaction system A is thermally reacted under organic solvent thermal conditions, and the supernatant of the thermally reacted reaction system A is filtered, crystallized at low temperature, and washed to obtain a fluorine-bridged rare earth molecular cluster magnetic refrigeration material. Specifically, the reaction system A is thermally reacted at a temperature of 80-160°C for 24-72 hours, and then the reaction system A after the thermal reaction is filtered with the supernatant, crystallized at low temperature, and washed to obtain the fluorine-containing bridge. Rare earth molecular cluster magnet...

Embodiment 1

[0044] 0.75g gadolinium pivalate (Gd(piv) 3 (Hpiv) 3 ) and 0.074g ammonium fluoride (NH 4 F) Add 8 ml of N,N-dimethylformamide (DMF), stir for 10 minutes to make it fully mixed to obtain a mixture; transfer the mixture to a polytetrafluoroethylene-lined stainless steel reactor, and place the reactor at 80 In an oven at ℃, heat and react for 72 hours under the pressure naturally generated by the reactor;

[0045] After the reaction is completed, the reaction kettle is naturally lowered to room temperature, the supernatant in the kettle is taken out, filtered, and placed in a minus 40 degree environment for cooling and crystallization for 24 hours, and finally pure colorless Gd 6 f 8 (piv) 10 (Hpiv) 4 The DMF crystal was washed three times with cold DMF, and the crystal yield was greater than 70% (calculated based on Gd). The crystal contained a new zero-dimensional structure, and the crystal structure was determined by single crystal X-ray diffraction analysis.

[0046] s...

Embodiment 2

[0050] 0.185g gadolinium pivalate (Gd(piv) 3 (Hpiv) 3 ) and 0.037g ammonium fluoride (NH 4 F) Add to 2 ml of methanol and stir for 10 minutes. Transfer the mixture into a polytetrafluoroethylene-lined stainless steel reaction kettle, place the reaction kettle in an oven at 160°C, and heat and react for 24 hours under the pressure naturally generated by the reaction kettle;

[0051] After the reaction is completed, the reaction kettle is naturally lowered to room temperature, the supernatant in the kettle is taken out, filtered, and placed at minus 40 degrees for cooling and crystallization for 24 hours, and finally pure light purple Gd is obtained. 6 f 8 (piv) 10 (Hpiv) 4 DMF crystals, washed three times with cold DMF, the crystal yield was greater than 30% (calculated based on Gd), and the crystal structure was determined by single crystal X-ray diffraction analysis, which was consistent with the previous Gd 6 f 8 (piv) 10 (Hpiv) 4 The crystal structure of DMF is con...

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Abstract

The invention discloses a fluorine bridged rare earth molecular cluster magnetic refrigeration material and a preparation method thereof. By adopting a solvothermal synthesis method, an air-stable fluorine bridged rare earth molecular cluster magnet is obtained through the reaction of a rare earth metal salt and a fluorine source. Refrigeration material, the unique weak ferromagnetic exchange makes the magnetic entropy change more difficult to saturate under low temperature and low field, and the magnetic refrigeration effect is better. The magnetic refrigeration material of fluorine bridged rare earth molecular cluster is a cluster compound, which is soluble in organic solvents, easy to process, and easy to combine with other materials or refrigeration sites, which can accurately reduce the specified temperature. The temperature in the region has a large magnetic entropy change in the low temperature region, which is an ideal material for low-temperature magnetic refrigeration materials. Due to the weak ferromagnetic exchange between rare earth ions in the cluster compound, the magnetic entropy change of the material at low temperature and low magnetic field is caused. high.

Description

technical field [0001] The invention belongs to the technical field of material science and relates to a magnetic functional material, in particular to a fluorine-bridged rare earth molecular cluster magnetic refrigeration material and a preparation method. Background technique [0002] Cryogenic refrigeration technology plays a very important role in gas liquefaction, high energy physics, superconducting technology, aerospace and other fields. At present, the low temperature acquisition methods mainly include phase change refrigeration (liquid, solid), expansion refrigeration, thermoelectric refrigeration, radiation refrigeration, adsorption refrigeration, helium-3 refrigeration and magnetic refrigeration. Among them, the main method to obtain and maintain the temperature below 4.2K is to use the compression-expansion cycle of liquid helium. For the temperature range below 2K, it is generally necessary to use rare and expensive helium-3, which has low efficiency and high p...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): H01F1/01H01F41/00C07F5/00
CPCC07F5/003H01F1/017H01F41/00
Inventor 郑彦臻凌博恺
Owner 西安交通大学深圳研究院
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