Structural Transition in the Hidden Ordered Phase of CeCoSi

Abstract

We have performed X-ray diffraction experiments on a single crystalline CeCoSi to investigate the unresolved ordered phase below $T_0\sim 12$ K. We have discovered that a triclinic lattice distortion takes place below $T_0$, which is further modified in the subsequent antiferromagnetic ordered phase. The structural domains can be selected by applying a magnetic field, indicating that some electronic ordering exists behind and affects the magnetic anisotropy in the hidden ordered phase below $T_0$. The transition at $T_0$, although the order parameter is still unknown, is associated with the maximum in the $c$-axis lattice parameter. In magnetic fields along $[1,0,0]$, the structural transition temperature, named as $T_{\text{s1}}$, deviates from $T_0$ and decreases with increasing the field, whereas $T_0$ increases. This shows that the hidden ordered phase without triclinic distortion exists between $T_{\text{s1}}$ and $T_0$. The results for $H\parallel [1,1,0]$ are also reported.

8 pages, 10 figures, 12 figures in the supplemental material, submitted to J. Phys. Soc. Jpn

References in corpus (4)

• Multipole expansion for magnetic structures: A generation scheme for symmetry-adapted orthonormal basis set in crystallographic point group
• Odd-Parity Multipoles by Staggered Magnetic Dipole and Electric Quadrupole Orderings in CeCoSi
• NQR and NMR spectra in odd-parity multipole material CeCoSi
• Unusual Nonmagnetic Ordered State in CeCoSi Revealed by ${}^{59}$Co-NMR and NQR Measurements

Cited by in corpus (2)

• Ferroic quadrupolar ordering in CeCoSi revealed using ${}^{59}$Co-NMR measurements
• RKKY Interactions and Multipole Order in Ab initio Wannier Model of CeCoSi