The Spin-Reorientation Transition in TmFeO3

摘要

X-ray magnetic circular and linear dichroism (XMCD and XMLD) have been usedto investigate the Fe magnetic response during the spin reorientationtransition (SRT) in TmFeO3. These experiments are complemented with resonantmagnetic diffraction experiments at the Tm M5 edge to study simultaneously theinduced magnetic order in the Tm 4f shell and the behavior of the Tm orbitalsthrough the SRT. Comparing the Fe XMLD results with neutron diffraction andmagnetization measurements on the same sample indicate that the SRT has anenhanced temperature range in the near surface region. This view is supportedby the resonant soft x-ray diffraction results at the Tm M5 edge. These find aninduced magnetic moment on the Tm sites, which is well-described by a dipolarmean field model originating from the Fe moments. Even though such a model candescribe the 4f response in the experiments, it is insufficient to describe theSRT even when considering a change in the 4f anisotropy. Moreover, the resultsof the Fe XMCD are indicative of a decoupling of spin canting andantiferromagnetic spin rotation in the near surface regime close to the SRT,which remains to be understood.