Synthesis, structural and magnetic properties of spin ladder compound Ca1−xCoxCu2O3

Abstract MCu 2 O 3 (M=Ca and Co) system has two-leg spin ladder structure similar to that of the prototype SrCu 2 O 3 system except that the rungs are buckled with an angle of 123° and 105° for CaCu 2 O 3 and CoCu 2 O 3 compounds, respectively. We have synthesized powder samples of (Ca 1− x Co x )Cu 2 O 3 ( x =0.00–1.00) by the solid state reaction method and their structural and magnetic properties have been investigated. All the synthesized compounds crystallize in orthorhombic structure with space group Pmmn. Lattice parameters of (Ca 1− x Co x )Cu 2 O 3 decrease with the increase in Co content. DC magnetic susceptibility χ ( T ) results of the end products CaCu 2 O 3 and CoCu 2 O 3 show antiferromagnetic transition ( T N ) at 27 and 215 K, respectively. Co doping into (Ca 1− x Co x )Cu 2 O 3 enhances its T N systematically with increasing Co concentration. The χ ( T ) of CoCu 2 O 3 shows a broad transition with the peak temperature around 215 K and it was found to be field independent up to 90 kOe. The ambiguity concerning the transition was ruled out by recording the temperature dependent X-ray diffraction pattern on CoCu 2 O 3 system, which indicated that there is no structural transition in the investigated temperature range of 115–300 K. Further, specific heat measurement on CoCu 2 O 3 confirms the magnetic phase transition by the appearance of a sharp peak at 215 K.