Investigation of the magnetism and magnetocaloric effect in the R2CoAl3 (R = Gd, Tb, Dy, and Ho) compounds

The crystal structure, magnetic properties and magnetocaloric effect (MCE) of R2CoAl3 (R = Gd, Tb, Dy, and Ho) compounds have been investigated. The refinement results proved that the samples are crystallized in MgCu2-type structure with space group of Fd-3m. The R2CoAl3 compounds undergo a paramagnetic to ferromagnetic phase transition (second ordered) and exhibit considerable reversible MCE around Curie temperatures TC of 70 K, 47 K, 33 K, and 20 K for R = Gd, Tb, Dy, and Ho, respectively. For the magnetic field change of 0–7 T, the maximum values of magnetic entropy change (−ΔSMmax) are 16.2, 10.6, 9.4, 16.5 J/kg K for R = Gd, Tb, Dy, and Ho, respectively. The considerable MCE with no hysteresis and wide working temperature span suggests that these materials could be promising candidates for magnetic refrigeration. •The R2CoAl3 (R = Gd, Tb, Dy, and Ho) compounds were synthesized.•Structure, magnetism and magnetocaloric effect (MCE) were studied.•A considerable reversible MCE was observed.•The origin of MCE and its potential application in R2CoAl3 were discussed.