Structural, electronic, and magnetic entropy contributions of the orbital order–disorder transition in LaMnO₃

Jahn–Teller distortion relaxation across the LaMnO3+Δphase diagram

“…The continuous relaxation of the MnO 6 octahedra distortions is observed until the rhombohedric composition is reached. As in the La 1−x Ca x MnO 3 report by Bozin et al [10], here, away from the stoichiometric compound, the presence of fully JT distorted Mn 3+ O 6 octahedra in the Pbnm average lattice 6 A curious point is that the higher EFG principal component was observed in the more symmetric R phase (V zzO < V zzR ). However, a similar result was reported by Dogra et al in stoichiometric perovskites (see table 2).…”

“…perovskites with a rhombohedric lattice structure. 6 Note that in this rhombohedric phase the MnO 6 octahedra should be constrained by symmetry to be undistorted, i.e., equal Mn-O bond lengths in the MnO 6 octahedra.…”

“…The JT electron-lattice coupling has also, as direct consequence, a high-temperature orbital order with direct implications on the material properties. Indeed, it has been suggested that the onset of orbital order (concomitant with the JT transition), at temperatures as high as 780 K, is a necessary requirement for spin and charge order occurring at low temperature [6][7][8].…”

Local probe studies in the weakly Jahn–Teller distorted LaMnO3.08 manganite

“…This Jahn–Teller electron–lattice coupling has also as direct consequence a high temperature orbital order (OO) with direct implications on other materials properties. Indeed, it has been suggested that the onset of orbital order is a necessary requirement for spin and charge order at low temperature .…”

Role of orbital selectivity on crystal structures and electronic states in BiMnO$_3$ and LaMnO$_3$ perovskites

“…The high temperature (HT) phase (T > 800 K) of both LaMnO 3 and BiMnO 3 is perovskite-type structure with orthorhombic symmetry [29][30][31] (see Fig. 1a) with similar bad-metallic conductivity 29,[32][33][34] . At room temperature (RT) both compounds are insulating 29,35 and in LaMnO 3 the orthorhombic distortions increases with decreasing temperature but the symmetry remains orthorhombic 31 , while in BiMnO 3 the structure distorts to monoclinic symmetry [36][37][38] .…”