Effect of Zn- or Ni-substitution on specific heat in La1.875Ba0.125CuO4: role of spin interaction in stripe phase

We investigated the effect of Zn- or Ni-substitution on specific hear in La 1.875Ba0.125CuO4 where the electronic specific heat coefficient y, is large ly suppressed by the stripe phase formation. The measurements of specific h ear were carried out between 1.5 and 7 K for the polycrystallines samples o f La1.875Ba0.125Cu1-yMyO4 (M = Zn or Ni). From the y dependence of y in the Zn-doping case the stripe phase is Found to be fully destroyed by doping. While the result of the Ni-doping case shows that the stripe phase is not t otally broken. but may undergo a new pha ie. The difference between Zn- and Ni-doping cases indicates that the spin interaction plays an important rol e for the strips phase formation. (C) 2000 Elsevier Science B.V. All rights reserved.