Transition metal (dis)order in single crystal multicomponent rare earth perovskites

Abstract

The utilization of configurational entropy in materials design has accelerated the tailoring of oxides for a variety of technological applications. So called “high entropy” oxides (HEO) have more recently been investigated for their use in magnetocaloric refrigeration due to tunability of the spin glass phase. To advance our understanding of these magnetic interactions, we have grown single crystals ( 5 mm diameter, 3 cm length) of the multicomponent perovskite SmCo1/4Cr1/4Fe1/4Mn1/4O3 using the laser diode floating zone technique. This material deviates from its parent SmMO3 (MCo, Cr, Fe, Mn) magnetic behaviors by having two broad transitions with a large bifurcation in the zero-field cooled vs field cooled measurements. Measurements of magnetization as a function of field show spin canting of the transition metal ions, with exchange bias emerging as a function of temperature. Heat capacity measurements are utilized alongside the non-magnetic rare earth analog LaCo1/4Cr1/4Fe1/4Mn1/4O3 to understand the low temperature superexchange interactions. Such comparison supports the two magnetic sublattices operating at different energy scales. Overall single crystal growth of such HEO should be utilized due to the ease of growth using the floating zone technique and insight it gives into the magnetic characterization.