Muon spin spectroscopy in multiferroic (Cu,Zn)${}_3$Mo${}_2$O${}_9$

Abstract

We present the muon spin relaxation/rotation spectra in the multiferroic compound (Cu,Zn)${}_3$Mo${}_2$O${}_9$. The parent material Cu${}_3$Mo${}_2$O${}_9$ has a multiferroic phase below $T_{\mathrm{N}}$ = 8.0 K, where the canted antiferromagnetism and the ferroelectricity coexist. The asymmetry time spectra taken at RIKEN-RAL pulsed muon facility show a drastic change at $T_{\mathrm{N}}$. At low temperatures the weakly beating oscillation caused by the static internal magnetic fields in the antiferromagnetic phase was observed in Cu${}_3$Mo${}_2$O${}_9$ and the lightly ($0.5\%$) Zn-doped sample. From the fitting of the oscillating term, we obtain the order parameter in these samples: ferromagnetic moment in two sublattices of antiferromagnet. In the heavily ($5.0\%$) Zn-doped sample, the muon-spin oscillation is rapidly damped. The frequency-domain spectrum of this sample suggests a formation of magnetic superstructure.

8 pages, 5 figures, in press in JPS Conf. Proc. as a part of USM2013 Proceedings

References in corpus (2)

• Successive phase transitions to antiferromagnetic and weak-ferromagnetic long-range orders in quasi-one-dimensional antiferromagnet Cu${}_3$Mo${}_2$O${}_9$
• Electric polarization induced by Neel order without magnetic superlattice: experimental study of Cu3Mo2O9 and numerical study of a small spin cluster