Magnetic properties of the ladder compounds La2(Cu,Zn)2O5 and La8(Cu,Zn)7O19

Abstract Whereas La 2 (Cu 1− x Zn x ) 2 O 5 is a 4-leg ladder-compound and La 8 (Cu 1− x Zn x ) 7 O 19 has 5 legs the magnetic susceptibility χ of both series shows a very similar behaviour on temperature T as well as on the Zn doping level, which is supposed to be due to the similar Cu–O coordination in both series, but quite different from that in classical spin ladders. For low Zn doping ( x ⩽0.04) a spin-chain like behaviour is found. This quasi one-dimensional behaviour is strongly suppressed for both series for x ⩾0.04. Here the maximum in χ ( T ) disappears and χ ( T ) decreases monotonously with increasing T .