Orbital order-disorder transition in La(1-x)Nd(x)MnO(3) (x = 0.0-1.0) and La(1-x-y)Nd(yx)Sr(y)MnO(3) (x = 0.1; y = 0.05,0.1)

Abstract

The nature of orbital order-disorder transition has been studied in the La(1-x)Nd(x)MnO(3) (x = 0.0-1.0) series which covers the entire range between two end points - LaMnO(3) and NdMnO(3) - as well as in La(0.85)Nd(0.1)Sr(0.05)MnO(3) and La(0.8)Nd(0.1)Sr(0.1)MnO(3). It has been observed that the first-order nature of the transition gives way to higher order with the increase in "x" in the case of pure manganites. The latent heat (L) associated with the transition, first, drops with a steeper slope within x = 0.0-0.3 and, then, gradually over a range 0.3<x<0.9. This drop could, possibly, be due to evolution of finer orbital domain structure with "x". In the case of Sr-doped samples, the transition appears to be of higher-order nature even for a doping level 5 at%. In both cases, of course, the transition temperature T(JT) rises systematically with the drop in average A-site radius <r(A)> or rise in average Mn-O-Mn bond bending angle <cos^2(phi)> while no apparent correlation could be observed with doping induced disorder sigma^2. The cooperative nature of the orbital order, therefore, appears to be robust.

arXiv comment15 pages including 4 figures; pdf only

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Cited by in corpus (5)

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• Dielectric anomaly at the orbital order-disorder transition in LaMnO_(3+delta)
• Dielectric anomaly at T_N in LaMnO3
• The Effect of Disorder in an Orbitally Ordered Jahn-Teller Insulator
• Continuous first order orbital order-disorder transition in Nd1-xCaxMnO3