LAUSR

Abstract Polycrystalline samples of compositions in the perovskite solid solution Sr2-xCaxCrSbO6 (x = 0, 0.25. 0.5, 0.75, 1.0, 1.25, 1.50, 1.75, 2.0) were synthesised and characterised by synchrotron x-ray diffraction and SQUID magnetometry. Neutron powder diffraction data were collected on the x = 0, 0.25, 0.5, 1.0, 1.5 and 2.0 compositions. It was found that Sr2CrSbO6 crystallised in the triclinic I 1 space group. The other compositions were all found to crystallise in the monoclinic space group P21/n although Sr1.5Ca0.5CrSbO6 was found to be phase separated into a calcium-deficient and calcium-rich phase, both having the space group P21/n. Sr2CrSbO6 was found to order antiferromagnetically at 12 K and the ordered Cr3+ moment was refined to be 2.39(1) µB. The antiferromagnetic order was rapidly quenched on doping with Ca and compositions with x ≥ 0.75 exhibited ferromagnetic order. TC increased with x to reach a maximum of 14 K at x = 2.0, with an ordered moment of 2.56(3) µB per Cr3+ cation. The tilt angles of the B-site octahedra about [110] and [001] increase from 5.4(1)° and 4.6(1)° to 13.7(1)° and 13.9(1)°, respectively, across the series; the switch from antiferromagnetism to ferromagnetism occurs when both tilts are at a value of ~ 8°.