The magnetocaloric effect of orthorhombic Gd(OH)CO ₃ has been experimentally studied, which exhibits −Δ S _m up to 66.4 J kg ⁻¹ K ⁻¹ (355 mJ cm ⁻³ K ⁻¹ ) for Δ H = 7 T and T = 1.8 K.

The large cryogenic magnetocaloric effect of a 3D oxydiacetate-bridged gadolinium–manganese MOF material, [Mn(H₂O)₆][MnGd(oda)₃]₂·6H₂O (1), was evaluated by magnetization and heat capacity measurements. A maximum −ΔS_m of 50.1 J kg⁻¹ K⁻¹ for ΔH = 70 kG along with significant entropy change at lower field was found on account of the weak Mn⋯Gd ferromagnetic interactions and the small molecular mass. This suggests that 1 could be considered as a potential coolant for liquid helium temperature applications.

Two 3D Gd( iii )-based coordination polymers, [Gd(glc)(Hglc)(H ₂ O)] _n · n H ₂ O ( 1 ) and [Gd(Hglc) ₃ ] _n ( 2 ) are reported. The MCE measurements indicate the weaker magnetic coupling in 2 produce a higher MCE than 1 , especially at moderate fields (−Δ S _m,max = 41.1 J kg ⁻¹ K ⁻¹ and 24.8 J kg ⁻¹ K ⁻¹ for 1 and 2 respectively at Δ H = 3 T).

The experimental results of the susceptibility, specific heat, magnetization, and electron spin resonance of $\mathrm{Cu}{\left({\mathrm{H}}_2\mathrm{O}\right)}_2\left({\mathrm{C}}_2{\mathrm{H}}_8{\mathrm{N}}_2\right)\mathrm{S}{\mathrm{O}}_4$ are reported. Despite the triangular arrangement of chemical bonds, the system is identified as an $S=1∕2$ Heisenberg antiferromagnet where the dominant exchange coupling $J∕k_B\approx -1.4\mathrm{K}$ is mediated by a square network of hydrogen bonds. The long-range ordering observed at $T_N=0.91\mathrm{K}$ is proposed to be Néel type. The possibility of tuning the strength of the exchange couplings in various directions is discussed.