paper

Ground state selection in XY pyrochlore antiferromagnets R $_{2}$ Ge $_{2}$ O $_{7}$ (R = Er, Yb)

arXiv:1508.04489 · doi:10.1103/PhysRevB.92.140407

Abstract

Elastic neutron scattering, ac susceptibility, and specific heat experiments on the pyrochlores Er $_{2}$ Ge $_{2}$ O $_{7}$ and Yb $_{2}$ Ge $_{2}$ O $_{7}$ show that both systems are antiferromagnetically ordered in the $I^_{5}$ manifold. The ground state is a $I ¨ _{3}$ phase for the Er sample and a $I ¨ _{2}$ or $I ¨ _{3}$ phase for the Yb sample, which suggests "Order by Disorder"(ObD) physics. Furthermore, we unify the various magnetic ground states of all known R $_{2}$ B $_{2}$ O $_{7}$ (R = Er, Yb, B = Sn, Ti, Ge) compounds through the enlarged XY type exchange interaction $J_{\pm}$ under chemical pressure. The mechanism for this evolution is discussed in terms of the phase diagram proposed in the theoretical study [Wong et al., Phys. Rev. B 88, 144402, (2013)].

5 pages, 4 figures, with supplemental material

Ground state selection in XY pyrochlore antiferromagnets R2​Ge2​O7​ (R = Er, Yb)

Abstract

Ground state selection in XY pyrochlore antiferromagnets R $_{2}$ Ge $_{2}$ O $_{7}$ (R = Er, Yb)