Suppression of magnetic order in CaCo1.86As2 with Fe substitution: Magnetization, neutron diffraction, and x-ray diffraction studies of Ca(Co1–xFex)yAs2

Magnetization, neutron diffraction, and high-energy x-ray diffraction results for Sn-flux grown single-crystal samples of Ca(Co_1–xFe_x)_yAs₂, 0 ≤ x ≤ 1, 1.86 ≤ y ≤ 2, are presented and reveal that A-type antiferromagnetic order, with ordered moments lying along the c axis, persists for x ≲ 0.12(1). The antiferromagnetic order is smoothly suppressed with increasing x, with both the ordered moment and Néel temperature linearly decreasing. Stripe-type antiferromagnetic order does not occur for x ≤ 0.25, nor does ferromagnetic order for x up to at least x = 0.104, and a smooth crossover from the collapsed-tetragonal (cT) phase of CaCo_1.86As₂ to the tetragonal (T) phase of CaFe₂As₂ occurs. Furthermore, these results suggest that hole doping CaCo_1.86As₂ has a less dramatic effect on the magnetism and structure than steric effects due to substituting Sr for Ca.