Er substitution effect in Gd 2 CoMnO 6 studied by investigations of magnetic property, magnetocaloric effect and the critical behavior

Abstract The double perovskite RE 2 BB 'O 6 has attracted research interest due to its stable crystal structure, competitive magnetic interactions and abundant magnetic sites. In this work, Er substitution effect on magnetic behavior, magnetocaloric effect, and the critical behavior of (Gd 1- x Er x ) 2 CoMnO 6 (0 ≤ x ≤ 1) were experimentally investigated. The magnetic measurements indicate a paramagnetic to ferromagnetic transition driven by 3 d -3 d interaction monotonically decreases from 112 K ( x = 0) to 96 K (x = 0.4), and further decreases to 66 K ( x = 1). The 3 d -4 f antiferromagnetic coupling is enhanced by the Er substitution and the metamagnetic transition in the latter half of both the descending (0→-60 kOe) and ascending branches (0→+60 kOe) of the hysteresis loop indicates the simultaneous flipping of the sublattice magnetic moments. In addition, the magnetocaloric responses characterized by magnetic entropy change -Δ S M (J×kg -1 ×K -1 ) under △ H = 60 kOe varies from 2.3 ( x = 0) to 3.2 ( x = 0.4) at T C , further reaching 4.4 ( x = 1), and from 19.2 ( x = 0) to 14.3 ( x = 0.4) at T = 4 K, and further to 9.4 ( x = 1). The critical and scaling analyses indicate the complex competition among different magnetic interactions, deviating from conventional universality classes, as well as the second-order magnetic transition in (Gd 1- x Er x ) 2 CoMnO 6 .