Magnetic and charge ordering properties of Bi0.6-x(RE)xCa0.4MnO3 (0.0 ≤ x ≤ 0.6) perovskite manganites

2012 ◽  
Vol 111 (7) ◽  
pp. 07E128 ◽  
Author(s):  
Kamlesh Yadav ◽  
M. P. Singh ◽  
H. K. Singh ◽  
F. S. Razavi ◽  
G. D. Varma
Keyword(s):  
Charge Ordering ◽  
Perovskite Manganites

Pressure effects on charge-ordering transitions in Perovskite manganites

1997 ◽  
Vol 55 (12) ◽  
pp. 7549-7556 ◽  
Author(s):  
Y. Moritomo ◽  
H. Kuwahara ◽  
Y. Tomioka ◽  
Y. Tokura
Keyword(s):  
Charge Ordering ◽  
Pressure Effects ◽  
Perovskite Manganites ◽  
Ordering Transitions

Probing the underlying charge ordering: Ruthenium-doped Sm1−xSrxMnO3 perovskite manganites

2001 ◽  
Vol 89 (4) ◽  
pp. 2232-2236 ◽  
Author(s):  
A. Maignan ◽  
C. Martin ◽  
M. Hervieu ◽  
B. Raveau ◽  
J. Hejtmanek
Keyword(s):  
Charge Ordering ◽  
Perovskite Manganites

STUDY OF NÉEL TEMPERATURE AND MULTIPLE PHASE COEXISTENCE IN Bi0.5Ca0.5-xBaxMnO3 (x = 0–0.10)

2012 ◽  
Vol 26 (08) ◽  
pp. 1250049
Author(s):  
RENWEN LI ◽  
LI PI ◽  
WEI TONG ◽  
LEI ZHANG ◽  
LANGSHENG LING ◽  
...  
Keyword(s):  
Magnetic Properties ◽  
Charge Ordering ◽  
Magnetic Data ◽  
Perovskite Manganites ◽  
Neel Temperature ◽  
Néel Temperature ◽  
Multiple Phase ◽  
Magnetic Analysis ◽  
Structural And Magnetic Properties ◽  
Lower Temperature

Structural and magnetic properties of Bi0.5 Ca0.5-xBaxMnO3 (x = 0, 0.03, 0.05, 0.07 and 0.10) samples with charge ordering (CO) state and C-type antiferromagnetic (AFM) magnetic structure have been studied systematically. With increasing Ba-doping level, both CO and AFM are weakened. From the micro-magnetic analysis, we clarify the ambiguity about the Néel temperature TN in bismuth-based perovskite manganites. We find that the paramagnetic (PM)-CO/AFM transition temperature TCO at high temperature is the onset temperature of the PM–AFM transition, while customarily so-called TN at low temperature indicates the finish of the PM–AFM transition. Both the macro- and micro-magnetic data show that, in all the samples, only AFM state coexists with PM matrix below CO transition and above TN, while AFM state coexists with ferromagnetic (FM) state and PM state at lower temperature below TN.

scholarly journals Structural and Magnetic States in Layered Manganites: An Expanding View of the Phase Diagram

1999 ◽  
Vol 602 ◽  
Author(s):  
J.F. Mitchell ◽  
J.E. Millburn ◽  
C. Ling ◽  
D.N. Argyriou ◽  
H. N. Bordallo
Keyword(s):  
Degrees Of Freedom ◽  
Hole Concentration ◽  
Charge Ordering ◽  
Perovskite Manganites ◽  
Electronic Interactions ◽  
Colossal Magnetoresistive ◽  
Reduced Dimensions ◽  
Incommensurate Magnetic Structure ◽  
Extreme Sensitivity ◽  
Magnetic States

AbstractColossal magnetoresistive (CMR) manganites display a spectacular range of structural, magnetic, and electronic phases as a function of hole concentration, temperature, magnetic field, etc. Although the bulk of research has concentrated on the 3-D perovskite manganites, the ability to study anisotropic magnetic and electronic interactions made available in reduced dimensions has accelerated interest in the layered Ruddlesden-Popper (R-P) phases of the manganite class. The quest for understanding the coupling among lattice, spin, and electronic degrees of freedom (and dimensionality) is driven by the availability of high quality materials. In this talk, we will present recent results on synthesis and magnetic properties of layered manganites from the La2−2xSr1+2xMn2O7 series in the Mn4+-rich regime x > 0.5. This region of the composition diagram is populated by antiferromagnetic structures that evolve from the A-type layered order to G-type “rocksalt” order as x increases. Between these two regimes is a wide region (0.7 < x < 0.9) where an incommensurate magnetic structure is observed. The IC structure joins spin canting and phase separation as a mode for mixed-valent manganites to accommodate FM/AF competition. Transport in these materials is dominated by highly insulating behavior, although a region close to x = 0.5 exhibits metal-nonmetal transitions and an extreme sensitivity to oxygen content. We suggest two possible explanations for this transport behavior at doping just above x=0.5: localization by oxygen defects or charge ordering of Mn3+/Mn4+ sites.

scholarly journals From double exchange to superexchange in charge ordering perovskite manganites

1998 ◽  
Author(s):  
W. Bao ◽  
J.D. Axe ◽  
C.H. Chen ◽  
S.W. Cheong ◽  
P. Schiffer ◽  
...  
Keyword(s):  
Double Exchange ◽  
Charge Ordering ◽  
Perovskite Manganites

Commensurate and incommensurate charge ordering in Perovskite manganites

1999 ◽  
Vol 09 (PR10) ◽  
pp. Pr10-307-Pr10-310 ◽  
Author(s):  
C. H. Chen ◽  
S. Mori ◽  
S.-W. Cheong
Keyword(s):  
Charge Ordering ◽  
Perovskite Manganites

scholarly journals Investigation of Lattice Effects in Rare Earth Manganites by 18O-isotope Exchange

1999 ◽  
Vol 52 (2) ◽  
pp. 235 ◽  
Author(s):  
R. Mahesh ◽  
M. Itoh
Keyword(s):  
Rare Earth ◽  
Colossal Magnetoresistance ◽  
Charge Ordering ◽  
Perovskite Manganites ◽  
Lattice Effects ◽  
Jahn Teller ◽  
18O Isotope ◽  
Ionic Size ◽  
Rare Earth Manganites ◽  
A Site

The strong coupling between the electron spin and lattice arising from the Jahn-Teller effect of manganese ions plays an important role in the mechanism of colossal magnetoresistance and related properties of the rare earth manganites. The lattice effects in this class of oxides have been extensively studied through the application of hydrostatic as well as chemical pressures and magnetic fields. The recently observed giant 18O isotope effect provides direct evidence for the formation of lattice polarons in manganites. Here we report the preliminary results of our investigations on a variety of normal as well as 18O isotope-exchanged perovskite manganites exhibiting colossal magnetoresistance and charge ordering. The observed isotope shift of Tc as well as that of Tco is correlated with the key parameters controlling the lattice such as the Mn 3+ content, the average ionic radius of the A-site cation ⟨rA⟩ , and the A-site ionic size disorder σ2 .

scholarly journals Effect of the Grain Size on the Magnetic Phase Separation in La0.8Sr0.2MnO3 by Magnetic Force Microscopy

2012 ◽  
Vol 18 (S5) ◽  
pp. 101-102
Author(s):  
P. De Sousa ◽  
N. Panwar ◽  
I. Bdikin ◽  
A. L. Kholkin ◽  
C. M. Fernandes ◽  
...  
Keyword(s):  
Grain Size ◽  
Phase Separation ◽  
Colossal Magnetoresistance ◽  
Room Temperature ◽  
Magnetic Phase ◽  
Magnetic Domain ◽  
Charge Ordering ◽  
Perovskite Manganites ◽  
Fundamental Study ◽  
Metallic Clusters

Perovskite manganites have been the focus of worldwide research during the last two decades because of the observation of colossal magnetoresistance (CMR) effect. These materials have potential applications in magnetic field sensors, spin filters, infrared bolometers and cathodes for solid oxide fuel cells. Such manganites are also important from the fundamental study viewpoint as they offer interplay among various degrees of freedom viz. spin, lattice and charge ordering. Moreover, phase separation may occur in manganites with low concentration of the dopant. In such scenario, ferromagnetic metallic clusters are embedded in antiferromagnetic insulating matrix. The fraction of these magnetic phases may vary from the nano- to micro-scale. With higher dopant concentration, the percolation of these magnetic metallic clusters leads to the apparent CMR effect. In this study we focus our attention to the low doped La0.8Sr0.2MnO3 (LSMO) manganite and investigate the possible magnetic phase separation and effect of variation in grain size on the magnetic domain size. La0.8Sr0.2MnO3 possesses Curie temperature (TC) higher than room temperature, therefore the material is supposed to be in the magnetic state at room temperature.

Magnetism and CMR in Electron Doped Perovskite and Layered Manganites

1999 ◽  
Vol 602 ◽  
Author(s):  
A. Maignan ◽  
C. Martin ◽  
M. Hervieu ◽  
B. Raveau
Keyword(s):  
Phase Diagrams ◽  
Magnetic Structure ◽  
Magnetic Phase ◽  
Structure Study ◽  
Charge Ordering ◽  
Perovskite Manganites ◽  
Doped Manganites ◽  
Magnetic Phase Diagrams

AbstractFrom the magnetic phase diagrams established for Ln1−xAExMnO3 manganites with x>0.5, it is shown that the magnetoresistance is only obtained for compositions of smallest average Asite cations <rA>. The magnetic structure study reveals that the small <rA> favors the coexistence of ferromagnetism with G-type antiferromagnetism. It is also shown that ferromagnetism can be induced in the Ln2−xAExMnO4 type electron doped manganites by using compositions with small Ln and AE cations and x values close to 1.90. Finally, manganse site doping by Cr, Co, Ni can be used to weaken the charge-ordering of the Mn4+ rich perovskite manganites (0.5<x≤0.8) and thus to induce CMR properties.

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