Tricarboxylate-based Gd(III) coordination polymers exhibiting large magnetocaloric effects

Area of Science:

• Materials Science
• Inorganic Chemistry
• Magnetism

Background:

• Coordination polymers based on lanthanide ions are explored for their unique magnetic and structural properties.
• Gadolinium(III) compounds are known for their significant magnetocaloric effects.

Purpose of the Study:

• To synthesize and characterize novel Gd(III) coordination polymers.
• To investigate the magnetic properties and magnetocaloric effects of these new materials.

Main Methods:

• Hydrothermal synthesis of two Gd(III) coordination polymers: [Gd(cit)(H2O)]∞ and [Gd(nta)(H2O)2]∞.
• Structural analysis of the 3D and double-layer structures.
• Magnetic property investigations, including measurements of magnetic susceptibility and heat capacity.
• Calculation of magnetocaloric effect parameters, such as maximum entropy change (-ΔS).

Main Results:

• Successful preparation of two Gd(III) coordination polymers with distinct structures.
• Identification of weak antiferromagnetic couplings between Gd(III) ions.
• Observation of large cryogenic magnetocaloric effects in both compounds.
• Maximum entropy changes of 31.3-32.2 J kg⁻¹ K⁻¹ at 2 K (ΔH = 3 T) and up to 41.5-42.0 J kg⁻¹ K⁻¹ at 2 K (ΔH = 7 T).

Conclusions:

• The synthesized Gd(III) coordination polymers exhibit excellent magnetocaloric properties.
• These materials are promising candidates for efficient low-temperature magnetic refrigeration.
• Structural features and magnetic interactions play a crucial role in achieving large magnetocaloric effects.