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All sourcesNASA NTRSDOE OSTI
DOE OSTI2021

Magnetic structure of magnetoelectric multiferroic HoFeWO 6

The polar magnetic oxide, HoFeWO6, is synthesized, and its crystal structure, magnetic structure, and thermodynamic properties are investigated. HoFeWO 6 forms the polar crystal structure (space group Pna2 1 (#33)) due to the cation ordering of W 6+ and Fe 3+ . An antiferromagnetic transition at T N = 17 K is accompanied by a significant change in magnetic entropy with a value of ≈ 5 J kg -1 K-1 in a 70 kOe applied field. Temperature dependent neutron diffraction and magnetization data indicate that the Fe sublattice orders in a strongly non-collinear and non-coplanar arrangement below T N . The Fe ordering initially leads to induced ordering of the Ho spins such that the Ho spins also show behavior of long-range ordering that is evident from the neutron diffraction measurements. Below T ≈ 4 K, the Ho spins order independently and pull the Fe spins toward the direction of Ho spins. A comparison with the magnetic structures and corresponding ferroelectric properties of other members of RMWO 6 (R = Y, Sm-Tm, M = Cr, Fe, V) family indicate that the spontaneous polarization is due to the magnetic structure specific to the Fe sublattice through magnetoelectric coupling whereas the polarization is independent of the Ho sublattice.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on SmTm3 by Materials Project

Tm3Sm is Uranium Silicide structured and crystallizes in the cubic Pm-3m space group. The structure is three-dimensional. Tm is bonded to eight equivalent Tm and four equivalent Sm atoms to form TmSm4Tm8 cuboctahedra that share corners with twelve equivalent TmSm4Tm8 cuboctahedra, edges with eight equivalent SmTm12 cuboctahedra, edges with sixteen equivalent TmSm4Tm8 cuboctahedra, faces with four equivalent SmTm12 cuboctahedra, and faces with fourteen equivalent TmSm4Tm8 cuboctahedra. All Tm–Tm bond lengths are 3.52 Å. All Tm–Sm bond lengths are 3.52 Å. Sm is bonded to twelve equivalent Tm atoms to form SmTm12 cuboctahedra that share corners with twelve equivalent SmTm12 cuboctahedra, edges with twenty-four equivalent TmSm4Tm8 cuboctahedra, faces with six equivalent SmTm12 cuboctahedra, and faces with twelve equivalent TmSm4Tm8 cuboctahedra.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on Sm3Tm by Materials Project

TmSm3 is alpha La-derived structured and crystallizes in the tetragonal I4/mmm space group. The structure is three-dimensional. Tm is bonded to twelve Sm atoms to form TmSm12 cuboctahedra that share corners with four equivalent TmSm12 cuboctahedra, corners with eight equivalent SmSm8Tm4 cuboctahedra, edges with eight equivalent TmSm12 cuboctahedra, edges with sixteen equivalent SmSm8Tm4 cuboctahedra, faces with four equivalent TmSm12 cuboctahedra, and faces with fourteen SmSm8Tm4 cuboctahedra. All Tm–Sm bond lengths are 3.61 Å. There are two inequivalent Sm sites. In the first Sm site, Sm is bonded to four equivalent Tm and eight Sm atoms to form SmSm8Tm4 cuboctahedra that share corners with twelve equivalent SmSm8Tm4 cuboctahedra, edges with eight equivalent TmSm12 cuboctahedra, edges with sixteen SmSm8Tm4 cuboctahedra, faces with four equivalent TmSm12 cuboctahedra, and faces with fourteen SmSm8Tm4 cuboctahedra. All Sm–Sm bond lengths are 3.61 Å. In the second Sm site, Sm is bonded to four equivalent Tm and eight equivalent Sm atoms to form SmSm8Tm4 cuboctahedra that share corners with four equivalent SmSm8Tm4 cuboctahedra, corners with eight equivalent TmSm12 cuboctahedra, edges with twenty-four SmSm8Tm4 cuboctahedra, faces with six equivalent TmSm12 cuboctahedra, and faces with twelve SmSm8Tm4 cuboctahedra.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on SmTm3 by Materials Project

Tm3Sm is beta Cu3Ti-like structured and crystallizes in the hexagonal P6_3/mmc space group. The structure is three-dimensional. Tm is bonded to eight equivalent Tm and four equivalent Sm atoms to form TmSm4Tm8 cuboctahedra that share corners with four equivalent SmTm12 cuboctahedra, corners with fourteen equivalent TmSm4Tm8 cuboctahedra, edges with six equivalent SmTm12 cuboctahedra, edges with twelve equivalent TmSm4Tm8 cuboctahedra, faces with four equivalent SmTm12 cuboctahedra, and faces with sixteen equivalent TmSm4Tm8 cuboctahedra. There are a spread of Tm–Tm bond distances ranging from 3.47–3.61 Å. There are two shorter (3.49 Å) and two longer (3.59 Å) Tm–Sm bond lengths. Sm is bonded to twelve equivalent Tm atoms to form SmTm12 cuboctahedra that share corners with six equivalent SmTm12 cuboctahedra, corners with twelve equivalent TmSm4Tm8 cuboctahedra, edges with eighteen equivalent TmSm4Tm8 cuboctahedra, faces with eight equivalent SmTm12 cuboctahedra, and faces with twelve equivalent TmSm4Tm8 cuboctahedra.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on Sm3Tm by Materials Project

TmSm3 is beta Cu3Ti-like structured and crystallizes in the hexagonal P6_3/mmc space group. The structure is three-dimensional. Tm is bonded to twelve equivalent Sm atoms to form TmSm12 cuboctahedra that share corners with six equivalent TmSm12 cuboctahedra, corners with twelve equivalent SmSm8Tm4 cuboctahedra, edges with eighteen equivalent SmSm8Tm4 cuboctahedra, faces with eight equivalent TmSm12 cuboctahedra, and faces with twelve equivalent SmSm8Tm4 cuboctahedra. There are six shorter (3.57 Å) and six longer (3.64 Å) Tm–Sm bond lengths. Sm is bonded to four equivalent Tm and eight equivalent Sm atoms to form SmSm8Tm4 cuboctahedra that share corners with four equivalent TmSm12 cuboctahedra, corners with fourteen equivalent SmSm8Tm4 cuboctahedra, edges with six equivalent TmSm12 cuboctahedra, edges with twelve equivalent SmSm8Tm4 cuboctahedra, faces with four equivalent TmSm12 cuboctahedra, and faces with sixteen equivalent SmSm8Tm4 cuboctahedra. There are a spread of Sm–Sm bond distances ranging from 3.57–3.65 Å.

36 MATERIALS SCIENCE↗