Magnetic and structural transitions in La1−x Sr x MnO3: T-x phase diagram

Abstract

Currently there is a great deal of interest in the investigation of substituted manganites R 1Ϫx A x MnO 3 , where R is a rare earth and A ϭCa,Sr, . . . This is due to the discovery of colossal magnetoresistance 1 as well as diverse magnetic and structural phase transformations 2,3 in these materials. These compounds all have the property that on doping with divalent Ca and Sr ions their magnetic structure changes from antiferromagnetic ͑with weak ferromagnetism͒ at xϭ0 to ferromagnetic at xϭ0.2±0.3, and their resistance decreases strongly. 2 Their crystal structure also undergoes a number of transformations. For example, as the Sr content in La 1Ϫx Sr x MnO 3 increases, the crystal symmetry changes from orthorhombic to rhombohedral, and in the intermediate Sr concentration range xϭ(0.1±0.15͒ an unusual polaron-ordered state is observed, which neutron diffraction data 4 show to be due to an ordered arrangement of heterovalent ions Mn 3ϩ /Mn 4ϩ in alternating ͑001͒ planes and to the formation of a corresponding superstructure.

Crystal field, Dzyaloshinsky-Moriya interaction, and orbital order inLa0.95Sr0.05MnODeisenhofer1, Erëmin2, Zakharov3 et al. 2002Phys. Rev. BSelf Cite532311View full textAdd to dashboardCite

“…The resistivity ρ of the sample under investigation is about 500 Ωcm at 200 K and 10 Ωcm at 300 K [16]. We estimated [10] that for resistivities ρ < 1 Ωcm the skin depth becomes smaller than the dimensions of the sample, which are about 1 mm.…”

Evidence of anisotropic magnetic polarons inLa0.94Sr0.06MnO3Hennion1, Moussa2, Biotteau3 et al. 2000Phys. Rev. B759410View full textAdd to dashboardCite

“…This enhanced ferromagnetic character can also be seen at smaller x, by a shift of the critical concentration x c for the metal-insulator transition. For instance, the x Sr =0.175 sample is metallic 14,15 , whereas the x Ca =0.194 one is still insulating 16 . Previous inelastic neutron measurements on low doped La 1−x Sr x MnO 3 , with x=0.05 17 and 0.09 18 , have reported a single spin wave branch, with AF interplane and F in-plane magnetic couplings.…”

Anomalous Electronic Anisotropy Triggered by Ferroelastic Coupling in Multiferroic Heterostructures

“…[ 1,5 ] In fact, two types of structural phase transitions are of suffi cient importance for perovskite oxides: cubic-tetragonal transition in PbTiO 3 , BaTiO 3 , and PbZr 1− x Ti x O 3 with x > 0.47, [6][7][8] and cubicrhombohedral transition in La 1− x S x MO for x > 0.17. [ 9,10 ] Below the transition temperature, ferroelastic domains form spontaneously to minimize the elastic energy in strained fi lms, such as YBa 2 Cu 3 O 7− d , [ 11 ] WO 3 , [ 12 ] or doped manganites [ 13 ] on various oriented substrates. Ferroelastic domain walls can effectively accommodate the residual epitaxial strain, and therefore play a crucial role in determining the functionality.…”