Magnetism and magnetocaloric effect in S = 7/2 Heisenberg antiferromagnet Gd2(fum)3(H2O)4·3H2O

Magnetic properties of Gd2(fum)3(H2O)4·3H2O were investigated by static and alternating susceptibility, specific heat and adiabatic magnetization. The material is characterized by weak antiferromagnetic interactions, arising predominantly from dipolar couplings that leads to magnetic ordering at TN = 0.19 K. A pronounced change in the magnetic entropy was found near the critical temperature. The magnetocaloric behavior estimated from specific heat data is confirmed by adiabatic magnetization above 0.2 K. In addition, adiabatic magnetization and demagnetization near the critical temperature revealed only a small hysteresis. Finally, the magnetothermal response and resulting refrigeration capacity of Gd2(fum)3(H2O)4·3H2O is compared with other magnetic refrigerants proposed for low-temperature applications.