ESR evidence for partial melting of the orbital order in LaMnO${}_3$ below the Jahn-Teller transition

Abstract

We report on high-temperature electron spin resonance studies of a detwinned LaMnO${}_3$ single crystal across the Jahn-Teller transition at $T_{\mathrm{JT}}$ = 750 K. The anisotropy of the linewidth and g-factor reflects the local Jahn-Teller distortions in the orbitally ordered phase. A clear jump in the linewidth accompanies the Jahn-Teller transition at $T_{\mathrm{JT}}$ = 750 K confirming that the transition is of first order. Already at $T^{\ast }$ = 550 K a significant decrease of the reduced linewidth is observed. This temperature scale is discussed with respect to the interaction of the $e_g$-electrons of the Mn${}^{3+}$-ions and the elastic field of the cooperative distortions. Our results support a partial melting of the orbital order along the antiferromagnetically coupled $b$-axis at $T^{\ast }$. The remaining two-dimensional orbital ordering within the ferromagnetically coupled $ac$-plane finally disappears together with the cooperative distortion at $T_{\mathrm{JT}}$. Moreover in our discussion we show that elastic strain field interactions can explain the melting of the orbital order and, thus, has to be taken into account to explain the orbital ordering in LaMnO${}_3$.

References in corpus (14)

• ESR study in lightly doped La_(1-x)Sr_(x)MnO_(3)
• The multiferroic phases of (Eu:Y)MnO3
• Orbital correlations in the pseudo-cubic \emph{O} and rhombohedral $R$-phases of LaMnO${}_3$
• Origin of Jahn-Teller distortion and orbital-order in LaMnO3
• Melting of the orbital order in LaMnO3 probed by NMR
• Magnetic-field-induced switching between ferroelectric phases in orthorhombic-distortion-controlled $R$MnO${}_3$
• The Orbital Order Parameter in La0.95Sr0.05MnO3 probed by Electron Spin Resonance
• Orbital-order melting in rare-earth manganites: the role of super-exchange
• Orbital fluctuations and orbital order below the Jahn-Teller transition in Sr3Cr2O8
• Korringa-like relaxation in the high-temperature phase of A-site ordered YBaMn2O6
• Local atomic and electronic structure in LaMnO_3 across the orbital ordering transition
• Volume contraction at the Jahn-Teller transition of LaMnO${}_3$
• Coupled spin-lattice fluctuations in a compound with orbital degrees of freedom: the Cr based dimer system Sr3Cr2O8
• Cooperative Jahn-Teller transition and resonant x-ray scattering in thin film $\mathrm{LaMn}{\mathrm{O}}_3$

Cited by in corpus (1)

• Electronic, structural, and magnetic properties of LaMnO${}_3$ phase transition at high temperature