Influence of the Jahn—Teller distortion on magnetic ordering in TbMn _{1− x} Fe _x O ₃

Abstract

The Jahn—Teller distortion plays an important role in determining the exchange interaction in rare-earth manganites. In this work we study the influence of the Jahn—Teller distortion on the magnetic structures of TbMn1−xFexO3 (x = 0, 0.02, 0.05, 0.10, and 0.20) single crystals in the basal MnO2 plane. The decrease in the quadruple splitting with the increasing Fe doping indicates the reduction of the Jahn—Teller distortion, which makes the nearest neighboring (NN) FM interaction dominant over the next nearest neighbor (NNN) AFM interaction. This alteration is favorable for the development of A-type AFM ordering instead of the spiral magnetic ordering, which collapses when x ≥ 0.05. The analysis of dielectric data indicates that the ferroelectricity is arising from the peculiar spiral magnetic ordering.

On the ferroelectric and magnetoelectric mechanisms in low Fe 3+ doped TbMnO 3

“…5,[10][11][12][13] However, only recently, interest has turned on to the effect of the substitution at the octahedral sites, where the experimental studies have been mainly focused on the effect on the magnetic behavior, and few on the multiferroic properties. [14][15][16][17][18][19][20][21] The effect of substitution at the octahedral sites with non-active Jahn-Teller ions on the ferroelectricity and magnetoelectric coupling still deserves attention, as the interpretation of the experimental results is controversial. This is the case of TbMn1-xMxO3, with M a trivalent transition metal ion: Cr 3+ , Fe 3+ and Co 3+ .…”

“…This is the case of TbMn1-xMxO3, with M a trivalent transition metal ion: Cr 3+ , Fe 3+ and Co 3+ . [15][16][17][18][19] The lowest energy electronic states of these ions, under the influence of an octahedral crystal field and in the high spin configuration, are described by t2g 3 eg 0 , t2g 3 eg 2 and t2g 4 eg 2 /(or t2g 6 eg 0 , for Co 3+ in the low spin state, also found in orthocobaltites), respectively, while for the Mn 3+ ion is t2g 3 eg 1 . Among the aforementioned ions, only Mn 3+ exhibits the Jahn-Teller effect.…”

“…27 Due to the fact that both Mn 3+ and Fe 3+ ions have the same radius, a fully solubility is obtained. [14][15][16] As the magnetic Mn 3+ ion is being substituted by another magnetic ion, the magnetic phase diagram is expected to be dependent on Fe 3+ substitution. 15,28 In fact, for Fe 3+ concentration up to around 50%, a weak-ferromagnetic phase emerges, wherein TN increases from 41 K to 300 K. 14,15,28 For higher concentrations, a continuous increase of the TN line is observed up to 650 K, whereas at lower temperatures a spin order reorientation occurs below a transition temperature that decreases from room temperature down to 10 K. 14,15,28 Very recently, powder neutron diffraction studies in Fe-substituted TbMnO3 has shown that the Mn long-range incommensurate spin ordering is destroyed by the introduction of Fe 3+ for concentrations of 10% to 25%, giving rise to a ferromagnetic component along the baxis resulting in a highly frustrated spin state.…”

Structural distortions and magnetisms in Fe-doped LaMn 1− x Fe x O 3 (0 < x ≤ 0.6)

“…Perovskite family oxides ABO 3 are particularly interesting materials, as their ground states are derived from the competition among lattice, spin, charge, and orbital degrees of freedom. [1,2] Octahedron BO 6 is the origin of many diverse properties in perovskite. [3,4] With slight substitution of elements at A or B site, the octahedron may distort with tilting and rotating and produces much more fascinating properties.…”