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

Abstract Magnetic properties of Gd 2 (fum) 3 (H 2 O) 4 ·3H 2 O 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 T N  = 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 Gd 2 (fum) 3 (H 2 O) 4 ·3H 2 O is compared with other magnetic refrigerants proposed for low-temperature applications.