Doping effects of Fe ion on magnetic anisotropy of YBa2Cu3Oy

• We clarified orientation effects of Fe-doped Y123 in modulated rotating fields.
• Y123 showed two different hard magnetic axes due to twin microstructures.
• The two hard magnetic axes in Fe-doped Y123 were [1 0 0] and [1 1 0] directions.
• Magnetic anisotropy of the [1 1 0] grain was higher than that of the [1 0 0] grain.

We report magnetic alignment of YBa2(Cu1−xFex)3Oy (Fe-doped Y123, x = 0–0.1) powders under modulated rotation magnetic fields (MRFs) and roles of Fe ion as a determination factor of magnetic anisotropy in Y123. The Fe-free and Fe-doped Y123 powder samples aligned in the MRF of 10 T showed two different orientation types of the hard axis in Y123 grains. From an X-ray rocking curve measurement for the magnetically aligned powder samples of the Fe-doped Y123, inplane magnetic anisotropy for Y123 grains with the hard axis parallel to the [1 1 0] direction was found to be higher than that for Y123 grains with the hard axis parallel to the [0 1 0] direction.