ALaMnBO6 (A = Ca, Sr, Ba; B = Fe, Ru) double perovskites

Ramesha, K.; Thangadurai, Venkataraman; Sutar, D.S.; Subramanyam, S. V.; Subbanna, G. N.; Gopalakrishnan, J.

doi:10.1016/s0025-5408(00)00248-8

Cited by 61 publications

(39 citation statements)

References 16 publications

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“…No atomic orderings of the A or B sites were found. These results are similar to what has been found in separate studies [21,27]. The refinement was finally carried out assuming a cubic Pm3m symmetry, with (Mn/Ru) located at the corners, (La/Ba) occupies the center of the cube, and O located between the (Mn/Ru) atoms, as shown in the inset to Fig.…”

Section: High-resolution Neutron Powder Diffractionsupporting

confidence: 82%

“…B-site doping, on the other hand, disrupts the electrically and magnetically active Mn-O-Mn network, weakening the DE interaction, and is believed to be detrimental to the conduction mechanism. A significant reduction in the Curie temperature due to Al, Fe, and Ti doping onto the B-sites has been reported [21], indicating that both the electrical and magnetic properties can be strongly affected by B-site doping. In this paper, we report on the crystalline structure and magnetic ordering of Mn and Ru in 50% A-site and 50% B-site doped (La 0.5 Ba 0.5 ) (Mn 0.5 Ru 0.5 )O 3 , studied by using dc magnetization, ac magnetic susceptibility, and neutron diffraction measurements.…”

Section: Introductionmentioning

confidence: 99%

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Magnetic ordering of Mn and Ru in (La_0.52Ba_0.48) (Mn_0.51Ru_0.49)O₃

Yang

et al. 2007

Physica Status Solidi (b)

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PACS 61.12. Ld, 75.25.+ z, 75.47.Gk Neutron diffraction, dc magnetization, and ac magnetic susceptibility measurements have been performed to study the magnetic properties of perovskite (La 0.52 Ba 0.48 ) (Mn 0.51 Ru 0.49 )O 3 . The compound crystallizes into a cubic Pm3m symmetry with a lattice constant of a = 3.9661(4) Å at room temperature. Two anomalies, at around 160 and 60 K, can clearly be seen in the ac susceptibility results, with the peak positions for both anomalies shifting to a higher temperature as a dc magnetic field is applied. Neutron magnetic diffraction measurements show that the anomalies that occur at high and low temperatures are associated with the ferromagnetic ordering of the Mn and the Ru spins, respectively. The ordering temperatures for the Mn and Ru spins were found to be T C (Mn) ≈ 195 K and T C (Ru) ≈ 80 K, with a saturated moment of 〈µ z-Mn 〉 = 2.21(5)µ B for the Mn spins and 〈µ z-Ru 〉 = 1.00(5)µ B for the Ru spins.

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Section: High-resolution Neutron Powder Diffractionsupporting

confidence: 82%

Section: Introductionmentioning

confidence: 99%

Magnetic ordering of Mn and Ru in (La_0.52Ba_0.48) (Mn_0.51Ru_0.49)O₃

Yang

et al. 2007

Physica Status Solidi (b)

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“…For A 2 MReO 6 (A= Ba, M = Fe, Mn, or Ni), [14] A 2 FeMoO 6 (A= Sr, Ba), [15] and ALaMnRuO 6 (A= Sr, Ba), the coupling between the two transition-metal cations is, in fact, antiferromagnetic despite the fact that the e g interaction should give ferromagnetism in all of these cases. [16] Instead, it is the t 2g interaction that dominates, giving rise to ferrimagnetism in these compounds. Sleight rationalized this behavior on the basis of energies of the t 2g levels for the two cations being much more similar than the energies of the e g levels.…”

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confidence: 99%

Magnetocapacitance and Magnetoresistance Near Room Temperature in a Ferromagnetic Semiconductor: La₂NiMnO₆

et al. 2005

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Materials that show various responses to multiple external stimuli enable novel device applications. The behavior of systems with strong coupling between magnetic and electronic degrees of freedom provides both challenges for solid-state theory as well as novel phenomena for applications such as colossal magnetoresistance in perovskite manganites. Similarly, a strong coupling between magnetism and dielectric properties in magnetic insulators or semiconductors should lead to devices based on the magnetodielectric effect, where the dielectric properties can be controlled by a magnetic field. Large magnetic-field-induced changes in the resistivity and dielectric properties of La 2 NiMnO 6 are found at temperatures as high as 280 K. This is a much higher temperature than previously observed for such a coupling between the magnetic, electric, and dielectric properties in a ferromagnetic semiconductor. The ferromagnetism of La 2 NiMnO 6 was confirmed through neutron-diffraction studies. La 2 NiMnO 6 is a rare example of a single-material platform with multiple functions, in which the spins, electric charge, and dielectric properties can be tuned by magnetic and/or electric fields.Spintronics (short for spin electronics) is a new technology that combines electronics with magnetics through the manipulation of electron spins. It offers the potential for nonvolatile memories, faster data processing speeds with less power usage, larger storage densities, and additional functionalities, such as quantum computation, which are not possible with conventional semiconductor devices.[1,2] Present spintronic devices, e.g., the giant magnetoresistor (GMR), used in readhead sensors, consist of ferromagnetic metallic alloys wherein spin-dependent scattering and tunneling effects have been successfully applied for commercial use. However, in order to fully achieve the potential of practical spintronic devices, the next generation of spintronic materials should be based on ambient-temperature ferromagnetic semiconductors or heterostructures incorporating ferromagnetic metals with nonmagnetic semiconductors, which enable their easy integration into existing electronic devices. The search for semiconducting materials that exhibit strong ferromagnetic behavior at or above room temperature has been extremely difficult due to conflicting requirements in the crystal structure, chemical bonding, and electronic properties of semiconductors and ferromagnetic materials. [1,3] Generally, ferromagnetic semiconductors and insulators only exhibit magnetic ordering at very low temperatures, e.g., EuS (Curie temperature, T c = 16 K), [4] EuO (T c = 77 K), [5] CdCr 2 Se 4 (T c = 130 K), [6] BiMnO 3 (T c = 100 K), [7] SeCuO 3 (T c = 25 K), [8] and diluted magnetic semiconductors, such as (Ga,Mn)As, [1] which precludes their use in devices. However, one exception is an ordered double perovskite, La 2 Ni 2+ Mn 4+ O 6 , an apparent ferromagnetic semiconductor that has a Curie temperature very close to room temperature (T c~2 80 K); [9±12] this is in the ra...

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“…39c Another interesting example of this kind is provided by LaAMnRuO 6 (A = Ca, Sr, Ba) where the redox process Mn III /Ru IV ↔ Mn IV /Ru III is likely important for the ferromagnetic and highly conducting properties. 40 Determination of oxidation states of metal atoms in transition metal compounds is an important issue that is often accomplished by titrimetric procedures based on oxidation-reduction reactions. 41 Thus, mixed valences of transition metals such as molybdenum, vanadium, manganese and copper in several perovskites and related oxides have been quantitatively determined by appropriate redox titrations.…”

Section: Oxidation/reductionmentioning

confidence: 99%

Quest for new materials: Inorganic chemistry plays a crucial role

Gopalakrishnan

Ramanathan

2009

J Chem Sci

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There is an endless quest for new materials to meet the demands of advancing technology. Thus, we need new magnetic and metallic/semiconducting materials for spintronics, new low-loss dielectrics for telecommunication, new multi-ferroic materials that combine both ferroelectricity and ferromagnetism for memory devices, new piezoelectrics that do not contain lead, new lithium containing solids for application as cathode/anode/electrolyte in lithium batteries, hydrogen storage materials for mobile/transport applications and catalyst materials that can convert, for example, methane to higher hydrocarbons, and the list is endless! Fortunately for us, chemistry -inorganic chemistry in particular -plays a crucial role in this quest. Most of the functional materials mentioned above are inorganic non-molecular solids, while much of the conventional inorganic chemistry deals with isolated molecules or molecular solids. Even so, the basic concepts that we learn in inorganic chemistry, for example, acidity/basicity, oxidation/reduction (potentials), crystal field theory, low spin-high spin/inner sphere-outer sphere complexes, role of d-electrons in transition metal chemistry, electron-transfer reactions, coordination geometries around metal atoms, Jahn-Teller distortion, metal-metal bonds, cation-anion (metal-nonmetal) redox competition in the stabilization of oxidation states -all find crucial application in the design and synthesis of inorganic solids possessing technologically important properties. An attempt has been made here to illustrate the role of inorganic chemistry in this endeavour, drawing examples from the literature as well as from the research work of my group.

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ALaMnBO6 (A = Ca, Sr, Ba; B = Fe, Ru) double perovskites

Cited by 61 publications

References 16 publications

Magnetic ordering of Mn and Ru in (La_0.52Ba_0.48) (Mn_0.51Ru_0.49)O₃

Magnetic ordering of Mn and Ru in (La_0.52Ba_0.48) (Mn_0.51Ru_0.49)O₃

Magnetocapacitance and Magnetoresistance Near Room Temperature in a Ferromagnetic Semiconductor: La₂NiMnO₆

Quest for new materials: Inorganic chemistry plays a crucial role

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ALaMnBO6 (A = Ca, Sr, Ba; B = Fe, Ru) double perovskites

Cited by 61 publications

References 16 publications

Magnetic ordering of Mn and Ru in (La0.52Ba0.48) (Mn0.51Ru0.49)O3

Magnetic ordering of Mn and Ru in (La0.52Ba0.48) (Mn0.51Ru0.49)O3

Magnetocapacitance and Magnetoresistance Near Room Temperature in a Ferromagnetic Semiconductor: La2NiMnO6

Quest for new materials: Inorganic chemistry plays a crucial role

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Magnetic ordering of Mn and Ru in (La_0.52Ba_0.48) (Mn_0.51Ru_0.49)O₃

Magnetic ordering of Mn and Ru in (La_0.52Ba_0.48) (Mn_0.51Ru_0.49)O₃

Magnetocapacitance and Magnetoresistance Near Room Temperature in a Ferromagnetic Semiconductor: La₂NiMnO₆