Magnetic phase diagram and multiferroicity ofBa3MnNb2O9: A spin-52triangular lattice antif

Abstract

We have performed magnetic, electric, thermal and neutron powder diffraction (NPD) experiments as well as density functional theory (DFT) calculations on Ba3MnNb2O9. All results suggest that Ba3MnNb2O9 is a spin-5/2 triangular lattice antiferromagnet (TLAF) with weak easy-axis anisotropy. At zero field, we observed a narrow two-step transition at TN1 = 3.4 K and TN2 = 3.0 K. The neutron diffraction measurement and the DFT calculation indicate a 120• spin structure in ab plane with out-of-plane canting at low temperatures. With increasing magnetic field, the 120• spin structure evolves into up-up-down (uud) and oblique phases showing successive magnetic phase transitions, which fits well to the theoretical prediction for the 2D Heisenberg TLAF with classical spins. Multiferroicity is observed when the spins are not collinear but suppressed in the uud and oblique phases.

Magnetic and electric properties of triangular lattice antiferromagnets Ba3ATa2O9 (A= Ni and Co)

“…In these materials, the complex spin structure accompanying ferroelectricity is stabilized by magnetic frustration [4]. Such behavior has been also observed in several triangular lattice antiferromagnets (TLAFs), such as Ba 3 CoNb 2 O 9 (Co 2+ , S ef f (effective spin) = 1/2) [5], Ba 3 NiNb 2 O 9 (Ni 2+ , S = 1) [6], Ba 3 MnNb 2 O 9 , (Mn 2+ , S = 5/2) [7], and RbFe(MoO 4 ) 2 (Fe 2+ , S = 5/2) [8]. In those systems, a spin structure called 120 degree ordered and Y phase is stabilized by the geometrical frustration at low fields.…”

Magnetic field-temperature phase diagram of multiferroic (NH4)2FeCl5·H2O

“…26 In triangular lattice antiferromagnets, exotic magnetic ground states and successive magnetic phase transitions have been observed. 41 Thus, the series of magnetic phase transitions observed in field also arises from the subtly competing exchange interactions in this system. These calculations also suggest that pressure may provide a pathway between the different A 2 FeX 5 ⋅H 2 O materials (Fig.…”

High-field magnetization and ESR in the triangular-lattice antiferromagnets Ba3MnSb2O9 and Ba3TNb2O9 (T=Ni, Co)

“…The compounds with general formula Ba 3 TT' 2 O 9 (T= 3d transition metals; T'= Sb, Nb) are TLAFs and have been paid much attention recently [13][14][15][16][17][18][19]. The compounds have 6H-perovskite-type structure [20], where the T and T' ions occupy the sites in the corner-sharing TO 6 octahedron and face-sharing T' 2 O 9 bi-octahedra, respectively.…”