Spin structure of the dopable quasi-one-dimensional copper oxide ${\mathrm{Ca}}_2{\mathrm{Y}}_2{\mathrm{Cu}}_5{\mathrm{O}}_{10}$

The $x=0\mathrm{}$ parent compound of the ${\mathrm{Ca}}_{2+x}{\mathrm{Y}}_{2-x}{\mathrm{Cu}}_5{\mathrm{O}}_{10}$ family of quasi-one-dimensional copper oxides was investigated by neutron powder diffraction. Long range antiferromagnetic order, with ferromagnetic alignment of the moments along the copper oxide chains, was observed below $T_N=29.5\mathrm{}\mathrm{K}.$ The low temperature ordered moment is $0.92{\mu }_B,$ close to the free ion value. The results are compared to observations on other magnetically ordered copper oxides.