Electronic interlayer coupling in the low-temperature tetragonal phase of La1.79Eu0.2Sr0.01CuO4

The electronic interlayer transport of the lightly doped antiferromagnet La1.79Eu0.2Sr0.01CuO4 has been studied by means of magnetoresistance measurements. The central problem addressed concerns the differences between the electronic interlayer coupling in the tetragonal low-temperature (LTT) phase and the orthorhombic low-temperature (LTO) phase. The key observation is that the spin-flip-induced drop in the c-axis magnetoresistance of the LTO phase, which is characteristic for pure La2-xSrxCuO4, dramatically decreases in the LTT phase. The results show that the transition from orthorhombic to tetragonal symmetry and from collinear to noncollinear antiferromagnetic spin structure eliminates the strain dependent anisotropic interlayer hopping as well as the concomitant spin-valve-type transport channel. Implications for the stripe ordered LTT phase of La2-xBaxCuO4 are briefly discussed.