Magnetic phase diagram of multiferroic delafossite CuFe1-yGayO2

Abstract

We report magnetic susceptibility measurements on nonmagnetic impurity-doped multiferroic CuFe1-yGayO2 with 0 y 0:08. The temperature versus Ga concentration magnetic phase diagram was obtained. Comparing the presently obtained phase diagram of CuFe1-yGayO2 with that of CuFe1-xAlxO2, we find that the stability of 4SL ground state for substitution of nonmagnetic ions does not depend on the nonmagnetic ionic radius significantly. On the other hand, the FEIC phase in CuFe1-yGayO2 exists in a wider region of 0:02 y 0:05 than CuFe 1-xAlxO2. We thus find that the local lattice distortion caused by large difference in ionic radii between Al3+ and Fe3+ affects the stability of the FEIC phase for nonmagnetic ion substitution significantly. © 2009 IOP Publishing Ltd.