Field-induced magnetic order and thermal conductivity in La1.87Sr0.13Cu1−yMyO4 (M = Zn, Ni)

We have measured the thermal conductivity in the ab plane, κab, of La1.87Sr0.13Cu1−yMyO4 (M = Zn, Ni; y = 0.01, 0.03, 0.10) single crystals in magnetic fields up to 14 T parallel to the c axis. By the application of magnetic field, κab has been found to be slightly suppressed at low temperatures for y(Zn) = 0.01 and y(Ni) = 0.01. The suppression of κab is smaller for y(Zn) = 0.01 than that for y(Ni) = 0.01. These results support the stripe-pinning model where the dynamically fluctuating stripes of spins and holes are regarded as being pinned by vortex cores, leading to the development of the static stripe order.