Identification of slow magnetic relaxation and magnetocoolant capabilities of heterobimetallic lanthanide-manganese metallacrown-like compounds

Abstract

Two types of 3d-4f compounds are presented, [DyIII4MnIII4(OH)2(O2C2H3)3(shi)4(H2shi)4(Hsal)3(DMF)4].3DMF (Dy-1) and [LnIII6MnIII2MnIV2(shi)6(Hshi)4(H2shi)2(Hsal)4(DMF)8].4H2O (Ln-2) (Ln = Dy or Gd, H3shi = salicylhydroxamic acid, H2sal = salicylic acid). While neither Dy-1 and Dy-2 demonstrated a significant barrier to magnetization relaxation, out-of-phase ac magnetic susceptibility was observed in both cases. Gd-2 showed potential as a magnetocoolent with gravimetric entropy changes reaching a maximum of 18.89 J.kg−1.K−1 at 3 K and ΔH = 7 T. This value represents approximately 53% of the theoretical maximum.