Jayasekara, W.T.; Pandey, A; Kreyssig, A.; Sangeetha, N.S.; Sapkota, A.; Kothapalli, K.; Anand, V.K.; Tian, W.; Vaknin, D.; Johnston, D.C.; McQueeney, R.J.; Goldman, A.I.; Ueland, B.G.: Suppression of magnetic order in CaCo1.86As2 with Fe substitution: Magnetization, neutron diffraction, and x-ray diffraction studies of Ca(Co1-xFex)yAs2. Physical Review B 95 (2017), p. 064425/1-12
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Magnetization, neutron diffraction, and high-energy x-ray diffraction results for Sn-flux grown single-crystal samples of Ca(Co1-xFex)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 (c_T) phase of CaCo1.86As2 to the tetragonal (T) phase of CaFe2As2 occurs. These results suggest that hole doping CaCo1.86As2 has a less dramatic effect on the magnetism and structure than steric effects due to substituting Sr for Ca.