Extraordinarily large intrinsic magnetodielectric coupling of the Tb member within the Haldane spin-chain family R2BaNiO5

Abstract

The Haldane spin-chain compound, Tb2BaNiO5, has been known to order antiferromagnetically below (TN=) 63 K. The present magnetic studies on the polycrystals bring out that there is another magnetic transition at a lower temperature (T2=) 25 K, with a pronounced magnetic-field induced metamagnetic and metaelectric behavior. Multiferroic features are found below T2 only, and not at TN. The most intriguing observation is that the observed change of dielectric constant (Δε) is intrinsic and largest (e.g., ~ 18% at 15 K) within this Haldane spin-chain family, R2BaNiO5. Taking into account the fact that this trend (that is, the largest value of Δε for Tb case within this family) correlates well with a similar trend in TN (with the values of TN being ~55, 58, 53 and 32 K for Gd, Dy, Ho and Er cases), we believe that the explanation usually offered for this TN behavior in rare-earth systems is applicable for this Δε behavior as well. That is, single-ion anisotropy following crystal-field splitting is responsible for the extraordinary magnetodielectric effect in this Tb case. To our knowledge, such an observation was not made in the past literature of multiferroics.

Unveiling ferrimagnetic ground state, anomalous behavior of the exchange-bias field around spin reorientation, and magnetoelectric coupling in YbCr1−xFexDalal1, Sarkar2, Rayaprol3 et al. 2020Phys. Rev. B19140View full textAdd to dashboardCite

“…In general, this cross coupling is strong in the type-II MFs where the ferroelectricity appears due to particular kind of spin structure of the materials, as classified by Khomskii [3,4]. Owing to the mutually exclusive nature of magnetism and ferroelectricity, several mechanisms have been proposed so far to understand the origin of multiferrocity in type-II MFs, such as, breaking of the inversion symmetry through asymmetric Dzyaloshinskii-Moriya (DM) interaction, the strong spin-dependent p-d hybridization, the exchange striction, and the single-ion magnetic anisotropy [5][6][7][8][9][10][11][12][13]. However, this cross coupling of spin and charge can also lead to another aspect of the MFs i.e., the magnetoelectric coupling effect in the insulating materials apart from the proper ferroelectric polarization, which could facilitate the pathway to engineer memory devices based on this effect and enlighten our knowledge to model the cutting-edge multiferroic materials [14,15].…”

Green sonochemical synthesis of BaDy2NiO5/Dy2O3 and BaDy2NiO5/NiO nanocomposites in the presence of core almond as a capping agent and their application as photocatalysts for the removal of organic dyes in water

“…Upadhyay, Garcia-Matres, and Basu et al demonstrated this behavior for Tb 2 -BaNiO 5 , Dy 2 BaNiO 5 , and Er 2 BaNiO 5 nickelates, respectively. 10,15,18 The DBNO NC synthesized in this work were used as photocatalysts. Fig.…”

“…17 Upadhyay et al studied the magnetic transitions of Tb 2 BaNiO 5 . 18 The Tb 2 BaNiO 5 has an AFM order below the Neel temperature (TN ¼ 63 K). In addition, Popova et al studied the magnetic structure and interchain interactions in the mixed-spin nickelate containing two different rare earth metals, (Er 0.25 Gd 0.75 ) 2 BaNiO 5 , using optical spectroscopy.…”

Unveiling spin-glass transition and antiferromagnetic order by μSR studies in spin-chain Sm2BaNiO5

“…Because of the 1D character several members of R 2 BaNiO 5 series exhibit Haldane gap in the excitation spectrum [10][11][12][13]. The multiferroic order associated with a significant magnetoelectric coupling has been proposed in some members of the R 2 BaNiO 5 series [14], such as Sm 2 BaNiO 5 [15], Dy 2 BaNiO 5 [16], Tb 2 BaNiO 5 [17], Er 2 BaNiO 5 [18], Gd 2 BaNiO 5 [19]. For Sm 2 BaNiO 5 a structural transition to a non-centrosymmetric Imm2 space group from the centrosymmetric Immm space group has been proposed for interpreting the ferroelectricity above magnetic ordering temperature [15].…”