Giant magnetocaloric effect in an exchange-frustrated GdCrTiO5 antiferromagnet

We report the role of exchange frustration on the magnetocaloric properties of GdCrTiO5. Due to the highly frustrated nature of magnetic interactions, in GdCrTiO5, the long-range antiferromagnetic ordering of Gd3+ moments occurs at a much lower temperature T-N = 0.9 K and the magnetic cooling power enhances dramatically relative to that observed in several geometrically frustrated systems. Below 5 K, the isothermal magnetic entropy change (-Delta S-m) is found to be 36 J kg(-1) K-1 for a field change (Delta H) of 7 T. -Delta S-m shows saturationlike behavior with decreasing T down to 2 K and is reversible in nature. The adiabatic temperature change Delta T-ad is 15.5 K for Delta H = 7 T. These magnetocaloric parameters are significantly larger than that reported for several potential magnetic refrigerants, even for small and moderate field changes. The present result not only suggests that GdCrTiO5 could be considered as a potential magnetic refrigerant at cryogenic temperatures but also promotes further studies on the role of exchange frustration on the magnetocaloric effect. In contrast, only the role of geometrical frustration on the magnetocaloric effect has been previously reported theoretically and experimentally investigated on very few systems.