Exploring the complex magnetic phase diagram ofCe2PdGe3: A neutron powder diffraction andμSRstudy

Abstract

The magnetic state of the tetragonal compound ${\mathrm{Ce}}_{2}{\mathrm{PdGe}}_{3}$, which crystallizes in the space group $P{4}_{2}/mmc$, a derivative of the $\ensuremath{\alpha}\text{\ensuremath{-}}{\mathrm{ThSi}}_{2}$ structure, has been investigated by magnetic susceptibility, heat capacity, muon spin relaxation $(\ensuremath{\mu}\mathrm{SR})$, and neutron diffraction measurements. Heat capacity data indicate two separate magnetic phase transitions at ${T}_{{N}_{1}}=10.7$ K and ${T}_{{N}_{2}}=2.3$ K. The presence of bulk long-range magnetic order is confirmed by our $\ensuremath{\mu}\mathrm{SR}$ study below 11 K, where a drop of nearly 2/3 in the muon initial asymmetry and a sharp increase in the muon depolarization rate were observed. Neutron powder diffraction reveals that only one out of two Ce sites becomes magnetically ordered with magnetic propagation vector $\ensuremath{\kappa}=(0)$ at ${T}_{{N}_{1}}$, adopting an antiferromagnetic arrangement of magnetic moments ${\ensuremath{\mu}}_{{\text{Ce}}^{3+}}=1.78(1){\ensuremath{\mu}}_{B}$ along the $c$ axis. At ${T}_{{N}_{2}}$ the second Ce site orders similarly, following the same magnetic propagation vector $\ensuremath{\kappa}=(0)$, showing, however, at the same time a significant ferromagnetic component within the tetragonal basal plane. A second propagation vector, $\ensuremath{\kappa}=\left(\frac{1}{2},0,\frac{1}{2}\right)$, appears concomitantly at ${T}_{{N}_{2}}$.