2003/09/10 by Andras Janossy, Titusz Feher, Andreas Erb
Physics and Astronomy · #cond-mat.supr-con #cond-mat.str-el
paper · pdf · doi:10.1103/physrevlett.91.177001
published as Phys. Rev. Lett. 91, 177001 (2003) · 4 pages, 4 figures, Accepted for publication in Phys. Rev. Lett
arxiv created 2003/09/10 · arxiv updated 2009/12/01
Hole induced changes in the antiferromagnetic structure of a lightly Ca doped Gd:Y1-xCaxBa2Cu3O6 copper oxide single crystal with x~0.008 is investigated by Gd3+ electron spin resonance. Holes do not localize to Ca2+ ions above 2.5 K since the charge distribution and spin susceptibility next to the Ca2+ are independent of temperature. Both hole doped and pristine crystals are magnetically twinned with an external magnetic field dependent antiferromagnetic domain structure. Unlike the undoped crystal, where the easy magnetic axis is along [100] at all temperatures, the easy direction in the hole doped crystal is along the [110] diagonal at low temperatures and changes gradually to the [100] direction between 10 K and 100 K. The transition is tentatively attributed to a magnetic anisotropy introduced by hole ordering.