The magnetic P-T phase diagram of langasite Ba3TaFe3Si2O14 at high hydrostatic pressures up to 38 GPa

Abstract

Multiferroicity and magnetoelectric coupling enhanced large magnetocaloric effect in DyFe0.5Cr0.5O3 Appl. Phys. Lett.Low temperature dielectric dispersion and relaxor like behavior in multiferroic Ba3NbFe3Si2O14

Equation of state and structural phase transitions in iron-based Ba3TaFe3Si2O14 langasite at high hydrostatic pressures

“…From the viewpoint of magnetic characteristics, an appreciable decrease in the parameter c in the struc tural phase transition at P tr2 ≈ 20 GPa should lead to a pronounced enhancement of the exchange coupling between iron ions located in the neighboring ab planes. This may be the cause of the giant increase in the Néel temperature observed recently at pressures exceeding 20 GPa [21].…”

“…The effect of applied pressure on magnetoelectric effects in mag netic materials with the triangular lattice was recently considered in [19,20]. Additional attention to this problem was stimulated by the observation of the giant stepwise increase in T N (from 27 to 120 K) in Ba 3 TaFe 3 Si 2 O 14 langasite at a high pressure (P > 20GPa) [21]. The relation between the magnetic prop erties and the crystal structure in the langasite family is still an open ended question.…”

“…The theoretical estimates [21,27] demonstrate that a spin crossover (the transition from the high spin state with S = 5/2 to the low spin state with S = 1/2) for Fe 3+ ions at the tetrahedral sites, which could give rise to the changes in the parameter characterizing the quadrupole coupling, cannot be expected in this pres sure range. Such pressure induced spin crossovers were observed in some oxides with Fe 3+ [28][29][30][31][32][33] and Fe 2+ [34][35][36] ions in oxygen octahedra.…”

High pressure and multiferroics materials: a happy marriage

“…Ba 3 TaFe 3 Si 2 O 14 , a member of the langasite family, crystallizes in the trigonal space group P321 with one formula unit per unit cell (Lyubutin et al, 2010). Gavriliuk et al (2013) investigated the pressure and temperature behavior of Ba 3 TaFe 3 Si 2 O 14 up to P = 38 GPa and down to T = 20 K by Nuclear Forward Scattering (NFS) and Raman spectroscopy. At P = 19.5 GPa a first-order pressure-induced phase transition has been observed.…”

PPMS-based set-up for Raman and luminescence spectroscopy at high magnetic field, high pressure and low temperature

“…Recently, the magnetic (and structural) properties of related langasites were found to be greatly affected by application of pressure [32], suggesting the relevance of T,P,Hdependent Raman studies on Ba 3 NbFe 3 Si 2 O 14 and other strongly correlated materials.…”