Crystallographic features of orbital ordering related to the C-type antiferromagnetic state in the simple perovskite manganite Ca1-xPrxMnO3

MRS Advances ◽  
2016 ◽  
Vol 1 (9) ◽  
pp. 579-584 ◽  
Author(s):  
Kentaro Kojima ◽  
Yasuhide Inoue ◽  
Yasumasa Koyama
Keyword(s):  
State Formation ◽  
Powder Diffraction ◽  
Electronic System ◽  
Perovskite Manganites ◽  
Perovskite Manganite ◽  
Orbital Ordering ◽  
X Ray ◽  
Notable Feature ◽  
Type Orbital ◽  
Antiferromagnetic Ordering

ABSTRACTIn the highly-correlated electronic system Ca1-xPrxMnO3 having the simple perovskite structure, it has been reported that there exists the C-type orbital-ordered (COO) state accompanying an antiferromagnetic ordering for 0.10 ≤ x ≤ 0.25. According to the previous studies concerning orbital-ordered states in simple perovskite manganites, the COO state was understood to be characterized by a spatial array of (3z2-r2)-type orbitals for 3d electrons in Mn ions. The notable feature of the COO state in Ca1-xPrxMnO3 is that the state with the monoclinic-P21/m symmetry appears as a result of the structural transition from the disordered state with the orthorhombic-Pnma symmetry. Compared with the COO-state formation from the cubic-Pm$\overline 3$m state, however, the formation from the disordered-Pnma state has not been understood yet. We have thus examined the crystallographic features of the formation of the COO state in Ca1-xPrxMnO3, mainly by x-ray powder diffraction and transmission electron microscopy. In the case of x = 0.16, for instance, the COO state was found to appear from the disordered-Pnma state around 90 K on cooling. The notable feature of the formation is that, in the Pnma state just before the COO-state formation, characteristic diffuse scattering appeared around each reflection in electron diffraction patterns, together with the splitting of the 200c reflection in x-ray powder diffraction profiles in the pseudo-cubic notation. Based on these experimental data, it is understood that the formation of the COO state in Ca1-xPrxMnO3 accompanies remarkable fluctuations of the C-type orbital ordering in the disordered-Pnma state.

Crystallographic Features of the C-Type Orbital-Ordered, and Charge- and Orbital-Ordered States in the Simple Perovskite Manganite Ca1-xLaxMnO3

2012 ◽  
Vol 706-709 ◽  
pp. 1612-1617
Author(s):  
Yasuhide Inoue ◽  
Masazumi Arao ◽  
Daisuke Shiga ◽  
Yasumasa Koyama
Keyword(s):  
Three Dimensional ◽  
Electronic System ◽  
Lattice System ◽  
Perovskite Manganite ◽  
Orbital Ordering ◽  
Transverse Lattice ◽  
Type Orbital ◽  
Antiferromagnetic Ordering ◽  
Monoclinic Distortion ◽  
Highly Correlated

The C-type orbital-ordered (CTOO), and charge-and orbital-ordered (COO) states are present in the simple perovskite manganite Ca1-xLaxMnO3, which has a three-dimensional highly-correlated electronic system. In this study, the crystallographic features of the CTOO and COO states have been investigated mainly by transmission electron microscopy to understand responses of a lattice system to these orderings. Of these two states, the cooling from the disordered orthorhombic Pnma (DO) state around x = 0.20 resulted in the CTOO state with the monoclinic P21/m symmetry. As a result of the monoclinic distortion as a response of the lattice system, the CTOO state consisted of a banded structure that was characterized by an alternating array of two monoclinic domains with different β values. In 0.30 < x < 0.50, on the other hand, the appearance of the COO state from the DO state on cooling accompanied a transverse lattice modulation with q = []DO as a response to orbital ordering in the COO state. The subsequent cooling in the COO state led to the antiferromagnetic ordering with a large lattice dilatation. In other words, no change in the crystal symmetry occurs in the appearance of the antiferromagnetic ordering.

Formation of the C-type Orbital-Ordered State in the Simple Perovskite Manganite Sr1-xSmxMnO3

MRS Advances ◽  
2016 ◽  
Vol 1 (9) ◽  
pp. 615-620 ◽  
Author(s):  
Misato Yamagata ◽  
Ayumi Shiratani ◽  
Yasuhide Inoue ◽  
Yasumasa Koyama
Keyword(s):  
Electronic System ◽  
The State ◽  
Tetragonal Symmetry ◽  
Perovskite Manganite ◽  
Orbital Ordering ◽  
Teller Distortion ◽  
Rotational Displacement ◽  
Type Orbital ◽  
Jahn Teller ◽  
Jahn Teller Distortion

ABSTRACTThe simple perovskite manganite Sr1-xSmxMnO3 (SSMO) has been reported to have a highly-correlated electronic system for eg-electrons in a Mn ion. According to the previous studies, the C-type orbital-ordered (COO) state with the I4/mcm symmetry was found to be formed from the disordered-cubic (DC) state on cooling. The feature of the COO state is that its crystal structure involves both the Jahn-Teller distortion to orbital ordering and the R25-type rotational displacement of oxygen octahedra. Because of the involvement of both the distortion and the displacement, their competition should be expected in the formation of the COO state. However, the detailed features of the competition have not been understood yet. Thus, the crystallographic features of the COO state in SSMO have been examined by x-ray powder diffraction and transmission electron microscopy. It was found that, when the Sm content increased from x = 0 at room temperature, the DC state changed into the COO state with the tetragonal symmetry around x = 0.13. The notable feature of the COO state is that the state is characterized by a nanometer-scaled banded structure consisting of an alternating array of two tetragonal bands. One tetragonal band consisted of the COO state involving both the Jahn-Teller distortion and the R25-type rotational displacement. But, there was only the latter displacement in the other, the state of which could be identified as a disordered tetragonal (DT) state. Based on this, it is understood that the COO-state formation from the DC state should take place via the appearance of the DT state, which may involve fluctuations of the C-type orbital ordering.

scholarly journals Resonant soft x-ray powder diffraction study to determine the orbital ordering in A-site-orderedSmBaMn2O6

2008 ◽  
Vol 77 (6) ◽  
Author(s):  
M. García-Fernández ◽  
U. Staub ◽  
Y. Bodenthin ◽  
S. M. Lawrence ◽  
A. M. Mulders ◽  
...  
Keyword(s):  
Diffraction Study ◽  
Powder Diffraction ◽  
Orbital Ordering ◽  
X Ray ◽  
A Site

Nickel-deficient Stannides Eu2Ni2–xSn5 – Structure, Magnetic Properties, and Mössbauer Spectroscopic Characterization

2009 ◽  
Vol 64 (10) ◽  
pp. 1107-1114 ◽  
Author(s):  
Thomas Harmening ◽  
Matthias Eul ◽  
Rainer Pöttgen
Keyword(s):  
Solid Solution ◽  
Magnetic Properties ◽  
Powder Diffraction ◽  
Spectroscopic Characterization ◽  
Structure Type ◽  
Induction Melting ◽  
X Ray ◽  
Antiferromagnetic Ordering ◽  
Divalent Europium ◽  
Experimental Magnetic Moment

New nickel-deficient stannides Eu2Ni2−xSn5 were synthesized by induction melting of the elements in sealed tantalum tubes. The solid solution was studied by X-ray powder diffraction and two crystal structures were refined on the basis of X-ray diffractometer data: Cmcm, a = 466.03(4), b = 3843.1(8), c = 462.92(9) pm, wR2 = 0.0469, 692 F2 values, 39 variables for Eu2Ni1.49(1)Sn5 and a = 466.11(9), b = 3820.1(8), c = 462.51(9) pm, wR2 = 0.0358, 695 F2 values, 39 variables for Eu2Ni1.35(1)Sn5. This new structure type can be considered as an intergrowth structure of CaBe2Ge2- and CrB-related slabs. The striking structural motifs are nickel-centered square pyramids which are condensed via common corners and edges. The layers of condensed NiSn5 units are separated by the europium atoms. The Ni1 sites within the CaBe2Ge2 slabs show significant defects which leads to split positions for one tin site. Eu2Ni1.50Sn5 shows Curie-Weiss behavior and an experimental magnetic moment of 7.74(1) μB / Eu atom, indicating stable divalent europium, as is also evident from 151Eu Mössbauer spectra. Antiferromagnetic ordering is detected at 3.5 K.

Resonant X-ray scattering study of perovskite-type vanadate RVO3

2010 ◽  
Vol 1 (SRMS-7) ◽  
Author(s):  
H. Nakao ◽  
D. Bizen ◽  
N. Shirane ◽  
K. Ikeuchi ◽  
Y. Murakami ◽  
...  
Keyword(s):  
Azimuthal Angle ◽  
Vanadium Oxides ◽  
Orbital Ordering ◽  
Orbital Order ◽  
X Ray ◽  
Type Orbital ◽  
X Ray Scattering ◽  
Scattering Study ◽  
Perovskite Type ◽  
Ray Scattering

The orbital ordering in perovskite-type vanadium oxides, RVO3 (R: rare earth), has been investigated by resonant X-ray scattering (RXS) near the V K-edge energy. The G-type orbital order, C-type orbital order and orbital disorder phases are elucidated on the basis of the azimuthal-angle and polarization dependence of the RXS signal reflecting the orbital ordering.

Possible Orbital-Ordered State in the Highly-Correlated Electronic Material Sr1-xCexMnO3

2014 ◽  
Vol 922 ◽  
pp. 230-236
Author(s):  
Takehiro Hanaoka ◽  
Yasuhide Inoue ◽  
Yasumasa Koyama
Keyword(s):  
Room Temperature ◽  
Three Dimensional ◽  
Electronic System ◽  
Careful Analysis ◽  
Perovskite Manganite ◽  
Orbital Ordering ◽  
Teller Distortion ◽  
Jahn Teller ◽  
Diffraction Patterns ◽  
Highly Correlated

The simple perovskite manganite Sr1-xCexMnO3 (SCMO) has a highly-correlated electronic system with a three-dimensional character. Because the presence of orbital-ordered states of eg electrons can be expected in SCMO, the crystallographic features of SCMO samples with 0.09 ≤ x ≤ 0.20 have been investigated mainly by transmission electron microscopy. In addition to fundamental reflections due to the simple perovskite structure, their electron diffraction patterns at room temperature exhibited both the presence of superlattice reflections at k = ()c in the cubic notation and the splitting of fundamental and superlattice reflections. The careful analysis of these reflections indicated that the superlattice reflections originated from the R25-type rotational displacement of oxygen octahedra about one of the <100>c directions. On the other hand, the splitting of the reflections was found to be due to a {110}c banded structure consisting of two tetragonal bands with different c/a values.　Because one of two tetragonal bands had the c/a value of about 1.028, the splitting reflects the introduction of the Jahn-Teller distortion as a response of a lattice system to orbital ordering. It is thus understood that the C-type orbital ordering of eg electrons should be involved in the state at room temperature for 0.09 ≤ x ≤ 0.20 in SCMO.

Raman Spectra of Multiferroics TbMnO3

2015 ◽  
Vol 1112 ◽  
pp. 23-26
Author(s):  
Ismudiati Puri Handayani ◽  
N. Mufti ◽  
Agustinus Agung Nugroho ◽  
T.T.M. Palstra ◽  
P.H.M. van Loosdrecht
Keyword(s):  
Low Energy ◽  
Perovskite Manganites ◽  
Perovskite Manganite ◽  
Optical Phonons ◽  
Strongly Coupled ◽  
Antiferromagnetic Ordering ◽  
Spin Ordering ◽  
Ordering Transition ◽  
Spiral State ◽  
Spin Spiral

The dream to have multifunctional materials has triggered an intense study of multiferroicity,i.e.of materials in which magnetic and electric polarizations are simultaneously present and strongly coupled. Here we study TbMnO3, a perovskite manganite exhibiting multiferroicity. It has an incommensurate antiferromagnetic ordering transition at 41 K and a transition into a multiferroic spin spiral state at 26 K. In this study, Raman spectroscopy has been used to elucidate the nature of the excitations related to phase transitions. We show that the optical phonons in TbMnO3resemble the phonon characteristics typical for perovskite manganites, corresponding to MnO6octahedral vibrations. The appearance of a new low energy modes at 32 cm-1, 40 cm-1, and 63 cm-1observed below 41 K signifies the antiferromagentic ordering in TbMnO3. The 32 cm- 1and 63 cm-1are interpreted as spin ordering activated phonon while the 40 cm-1is interpreted as spin ordering induced splitting of Tb quasi doublet cystal field level.

Er L3-edge resonant elastic X-ray scattering study of orbital ordering in ErVO3

2011 ◽  
Vol 1 (SRMS-7) ◽  
Author(s):  
K. Ikeuchi ◽  
H. Nakao ◽  
Y. Murakami ◽  
S. Miyasaka ◽  
Y. Tokura
Keyword(s):  
Absorption Edge ◽  
Orbital Ordering ◽  
X Ray ◽  
Type Orbital ◽  
X Ray Scattering ◽  
Scattering Study ◽  
Ray Scattering

Resonant elastic X-ray scattering (RXS) at the erbium absorption edge was investigated in the orbital-ordered compound ErVO3. An RXS signal resonating near the Er L3-edge was clearly observed at (1 0 0). Using this signal, we studied the relation between the anisotropy of the Er 5d orbital and the V 3d orbital ordering because the covalency between the Er 5d and V 3d orbitals is expected to stabilize the C-type orbital ordering of the V 3d electrons.

Features of the intermediate state appearing between the C- and A-type orbital-ordered states in the highly-correlated electronic system Sr1-xNdxMnO3

MRS Advances ◽  
2016 ◽  
Vol 1 (9) ◽  
pp. 603-608 ◽  
Author(s):  
Ayumi Shiratani ◽  
Hiroki Sato ◽  
Yasuhide Inoue ◽  
Yasumasa Koyama
Keyword(s):  
Electronic System ◽  
Oxide System ◽  
The State ◽  
State Change ◽  
Orbital Ordering ◽  
Type Orbital ◽  
Transmission Electron ◽  
Displacement Pattern ◽  
Highly Correlated ◽  
Image Position

ABSTRACTThe presence of the C- and A-type orbital-ordered states has been reported in the highly-correlated electronic system Sr1-xNdxMnO3 (SNMO). The interesting feature of the oxide system is that an increase in the Nd content leads to the (C-type → A-type) state change across a temperature-independent morphotropic phase boundary (MPB). Although structural fluctuations can be expected near the MPB, the detailed features of the state change have not been understood sufficiently. Thus, the crystallographic features of the state change in SNMO with 0.35 ≤ x ≤ 0.49 have been investigated mainly at 300 K, by x-ray powder diffraction and transmission electron microscopy. It was found that the C-type orbital-ordered state with the tetragonal-I4/mcm symmetry and the disordered orthorhombic-Imma state were present for 0.35 ≤ x ≤ 0.43 and for 0.45 ≤ x ≤ 0.49 at 300 K, respectively. The notable feature of the state change is that disordered regions with the cubic-Pm$\bar 3$ m symmetry were also found locally for x = 0.43, in addition to the C-type state. Because the rotational-displacement pattern for oxygen octahedra involved in the disordered-Imma state is the same as that in the A-type state, furthermore, the former disordered state may be regarded as a precursor state to the A-type orbital ordering.

New horizons for the structural characterization of stainless steel slags by X-ray powder diffraction

2007 ◽  
Vol 2007 (suppl_26) ◽  
pp. 61-66 ◽  
Author(s):  
B. Peplinski ◽  
B. Adamczyk ◽  
G. Kley ◽  
K. Adam ◽  
F. Emmerling ◽  
...  
Keyword(s):  
Stainless Steel ◽  
Powder Diffraction ◽  
Structural Characterization ◽  
X Ray ◽  
New Horizons
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