Synthesis, structural and magnetic properties of spin ladder compound Ca sub(1-xCo) sub(x)Cu sub(2O) sub(3)

MCu sub(2O) sub(3) (M=Ca and Co) system has two-leg spin ladder structure similar to that of the prototype SrCu sub(2O) sub(3) system except that the rungs are buckled with an angle of 123 degree and 105 degree for CaCu sub(2O) sub(3) and CoCu sub(2O) sub(3) compounds, respectively. We have synthesized powder samples of (Ca sub(1-xCo) sub(x))Cu sub(2O) sub(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 sub(1-xCo) sub(x))Cu sub(2O) sub(3) decrease with the increase in Co content. DC magnetic susceptibility [chi](T) results of the end products CaCu sub(2O) sub(3) and CoCu sub(2O) sub(3) show antiferromagnetic transition (T sub(N) at 27 and 215 K, respectively. Co doping into (Ca) sub(1)-xCo sub(x)Cu) sub(2)O sub(3 enhances its T) sub(N) systematically with increasing Co concentration. The [chi](T) of CoCu sub(2O) sub(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 sub(2O) sub(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 sub(2O) sub(3) confirms the magnetic phase transition by the appearance of a sharp peak at 215 K.