Magnetoelectric coupling in the honeycomb antiferromagnetCo4Nb2O9

Single crystal growth of Mn4Nb2O9 and its structure-magnetic coupling

“…An antiferromagnetic (AFM) transition is found at Néel temperature T N ¼ 108.4 K. In contrast to Co 4 Nb 2 O 9 , 7 the AFM order of Mn 4 Nb 2 O 9 single crystal is along c axis and the spin op transition does not occur even with a magnetic eld up to 7 T. A structural phase transition is observed with a-direction shrinkage and c-direction expansion around 110 K, which corresponds exactly to the T N of Mn 4 Nb 2 O 9 . The magnetic structure of our AFM Co 4 Nb 2 O 9 single crystal is different from a collinear arrangement with spin parallel to the trigonal axis as proposed previously by Bertaut et al 3 and resembles the Co 2+ magnetic moments found to be almost lying in the basal plane by Khanh et al 8 But the main difference between the samples, which is responsible for the different easy axis directions, is not clear yet. precisely controlled by adjusting the power of the lamps.…”

Magnetodielectric and magnetoelastic coupling in Co4Nb2O9 below Néel temperature

“…At the same time, the strain exhibits a drop below T N , and the magnetic field suppresses this anomaly, demonstrating magnetoelastic coupling in Co 4 Co 4 Nb 2 O 9 is a collinear antiferromagnet with a spin-flop transition at a critical field of about 12 kOe, and a dielectric peak around Néel temperature (T N ) under the magnetic field larger than this critical field is found by Kolodiazhnyi et al 1 Subsequently, magnetic field induced electric polarization and electric field control of magnetism is observed below T N by Fang et al 2 More recently, Khanh et al investigated magnetic structure and magnetoelectric response in single crystal sample, and the results suggest the in-plane antiferromagnetic order and the formation of a ferrotoroidic order in Co 4 Nb 2 O 9 . 3 However, none of them get much attention to the dielectric property below T N . In this paper, we found that the dielectric constant shows an upturn below T N , and the magnetic field of 5 T enhances this anomaly.…”

Materials and Life Science Experimental Facility (MLF) at the Japan Proton Accelerator Research Complex II: Neutron Scattering Instruments

“…A detailed study of the ferromagnetic spin waves in the metallic magnet SrRuO 3 by means of neutron Brillouin scattering using the HRC spectrometer revealed a unique temperature dependence of the spin gap, which can be attributed to the Berry curvature of the Weyl fermion [57]. A study of the magnetic structure of the honeycomb antiferromagnet Co 4 Nb 2 O 9 using the single-crystal diffractometer SENJU revealed that the magnetic structure is different from that proposed previously, but it better explains the magnetic properties as well as the magnetoelectric response of this compound [153]. In the following, we show in greater detail a recent inelastic scattering study on magnetic fluctuations in iron-based superconductors performed using the 4SEASONS spectrometer [48].…”