Gd+GdZn biphasic magnetic composites synthesized in a single preparation step: Increasing refrigerant capacity without decreasing magnetic entropy change

• Magnetocaloric composites of Gd + GdZn are synthesized in a single preparation step.
• It is a simplified preparation method of bulk composites vs. the conventional one.
• Improved table-like MCE is achieved, good for Ericsson-type refrigeration cycles.
• Improved thermal contact between phases, enhanced RC   and no relevant loss of ΔSMpk.
• MCE results of Gd + GdZn composites are modeled by considering non-interacting phases.

Biphasic Gd + GdZn composites (Gd(50+x)Zn(50−x); x = 0, 5, 15 and 25 at.%) were successfully obtained in a single fabrication step by induction melting. X-ray microdiffraction results reveal the homogeneity of all the prepared samples and indicate a combination of GdZn and Gd phases with different proportions. With this method, the main drawbacks of preparing composites have been avoided, providing the additional advantage of enhanced thermal conductivity between phases. The biphasic Gd + GdZn composite shows an enhanced refrigerant capacity in comparison to Gd (11%) as well as to single phase GdZn (45%). Heat capacity measurements provide an adiabatic temperature change of around 3.5 K for 20 kOe for the optimal composite.