Partially-disordered to frozen-state crossover induced magnetocaloric properties of the antiferromagnetic one-dimensional spin-chain Sr 3 CoIrO 6

Low-dimensional and geometrically frustrated spin-chain Sr 3 (Co/Ni)IrO 6 compounds exhibit interesting physical phenomena due to the exotic anisotropy associated with the spin-orbit entangled Ir 4+ state. Temperature dependent magnetic susceptibility of polycrystalline Sr 3 CoIrO 6 characterizes the partially-disordered antiferromagnetic with T N1 � 90 K and the frozen state of this antiferromagnetic order below T N2 � 30 K. The fitting of �T versus T (K) data to the Ising model reveal that the intra-chain exchange interactions are ferromagnetic, whereas the inter-chain exchange correlations are antiferromagnetic. Field-induced alteration of the partially-disordered antiferromagnetic state in the temperature regime of T N1 � T � T N2 is responsible for the anomalous magnetic hysteresis loop. Further, a large value of isothermal magnetic-entropy change (�S M � 22 J kg -1 K -1 for 7 T), absence of thermal hysteresis in magnetization and highly insulating nature consents Sr 3 CoIrO 6 to be classified as a good magnetocaloric material for the lowerature refrigeration. © 2019 IOP Publishing Ltd