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(a) Magnetic susceptibility and inverse magnetic susceptibility of Ba5Sn1.1Mn3.9O15 measured at 1000 Oe, (b) magnetic susceptibility under zero filed cooling and field cooling (20 Oe) between 2 and 50 K, and the field dependence of magnetization at 2 K (inset) of Ba5Sn1.1Mn3.9O15.
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![Fig. 3. CBED patterns of Ba5Sn1.1Mn3.9O15 along (a) [0 0 1], (b) [ ¯ 1...](profile/Congling-Yin/publication/240366179/figure/fig3/AS:760627878440962@1558359226645/CBED-patterns-of-Ba5Sn11Mn39O15-along-a-0-0-1-b-1-1-0-and-c-5-4-0_Q320.jpg)
A new compound Ba5Sn1.1Mn3.9O15 has been synthesized at 1300°C by solid-state reaction. The structure was characterized by X-ray, electron and neutron diffraction methods. Ba5Sn1.1Mn3.9O15 crystallizes in hexagonal space group P63/mmc with a=5.717Å and c=23.534Å. The magnetic measurement reveals that Ba5Sn1.1Mn3.9O15 has a spin glass transition at...
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... dependent DC magnetic susceptibility is shown in Fig. 5. The susceptibility changes little in 100-300 K and starts to increase smoothly as temperature goes down. This indicates the sample is a paramagnetic insulator with anti-ferromagnetic interaction between magnetic moments above 100 K. A slop change of the magnetic susceptibility is observed at about 7 K (shown in Fig 5a), below which ...
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... indicates the sample is a paramagnetic insulator with anti-ferromagnetic interaction between magnetic moments above 100 K. A slop change of the magnetic susceptibility is observed at about 7 K (shown in Fig 5a), below which ZFC and FC magnetic susceptibility starts to diverge (shown in Fig. 5b). In addition, the AC magnetic susceptibility shows a peak at about 7 K, which is slightly frequency-dependent as shown in Fig. 6. ...
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... starts to increase smoothly as temperature goes down. This indicates the sample is a paramagnetic insulator with anti-ferromagnetic interaction between magnetic moments above 100 K. A slop change of the magnetic susceptibility is observed at about 7 K (shown in Fig 5a), below which ZFC and FC magnetic susceptibility starts to diverge (shown in Fig. 5b). In addition, the AC magnetic susceptibility shows a peak at about 7 K, which is slightly frequency-dependent as shown in Fig. 6. This suggests the magnetic transition at 7 K is a spin glass transition [28]. Small loop observed in M-H curve measured at 2 K agrees with such behavior. A second peak observed at about 36 K in AC magnetic ...
Citations
... This indicates the paramagnetic behavior between 400 and T N . In the temperature rages 266-273 K and 308-296 K, the susceptibility values are almost constant inferring paramagneticantiferromagnetic interactions between magnetic moments [53]. For further cooling below T N , the samples become antiferromagnetic. ...
Undoped and In doped substoichiometric CdO nanostructured films were prepared via vapor transport method. Mixed phases of hexagonal Cd and cubic CdO were obtained. No peaks related to In or indium oxides were observed in the In doped CdO pattern. Net-like assembles of nanowires were observed for undoped CdO sample whereas a regular morphology of equally shaped grains was observed for In doped CdO sample. The evaluated room temperature electrical resistivity values for undoped and In doped CdO films were 1.56 × 10² and 2.31 × 10–2 Ωcm, respectively. The temperature dependent resistivity measurements elucidated the semiconducting behavior for undoped CdO films, whereas a semiconductor–metal with a transition around 367 K was obtained for In doped CdO film. The magnetic susceptibility showed paramagnetic-antiferromagnetic transition with Néel temperatures of 266 and 308 for undoped and In doped CdO samples, respectively.
A 12-layer hexagonal perovskite Ba4SbMn3O12 (space group: R3̄m; a = 5.72733(3) Å, and c = 28.1770(3) Å) has been synthesized by high-temperature solid-state reactions and studied using powder X-ray and neutron diffraction and magnetization measurements. This 12R polytype structure contains one corner-sharing (Sb, Mn)O6 octahedron and a trimer of face-sharing MnO6 octahedra per formula unit. Ba4SbMn3O12 displays a paramagnetic state of the Mn3 magnetic cluster at 100-200 K, which partially disassociates into individual Mn ions at 250-300 K. The ferromagnetic interaction between these Mn3 clusters is mainly mediated by Mn3+ at the M1 site, leading to dynamic ferromagnetic clusters below T D = ∼70 K and ferromagnetic spin freezing transition at T g = ∼11.5 K. The stability of Mn3 magnetic clusters in the 12R polytypes is related to the intracluster Mn-Mn distance.
A new solid solution of composition PbBiFe1-xMxO4 (M = Mn and Co, 0 ≤ x ≤ 0.15–0.2) with low structural dimensions has been synthesized by solid-state reaction at 873–923 K. The crystal structures have been investigated using X-ray and neutron diffraction. The presence of Co²⁺/Co³⁺ on the Fe³⁺ sites and oxygen vacancies in PbBiFe1-xCoxO4 is revealed by its unusual volume increase and TGA, while the volume contraction of PbBiFe1-xMnxO4 indicates the substitution of Mn⁴⁺/Mn³⁺ on the Fe³⁺ sites. This leads to unexpected greater and smaller metal-metal distances inside the chains for the Co and Mn case, respectively, compared with the undoped materials. All the PbBiFe1-xMxO4 materials display long-range antiferromagnetic order but are suppressed by cationic substitution, as evidenced by a decrease in TN. Additional intrinsic short-range ferro- (or ferri-) magnetic transitions in the Co-doped materials are evidenced by magnetic hysteresis and frequency-dependent χ’ peak around TF. The introduction of ferromagnetic intrachain clusters in PbBiFe1-xCoxO4 is rationalized through a competitive mechanism between direct AFM exchange interaction and 90°- type FM superexchange interactions, which provided insights to tune the magnetic properties and design low dimensional functional materials.
The new hexagonal perovskite phase of composition Ba4Sn1.1Mn2.9O12 has been synthesized by solid-state reactions at 1673 K. The crystal structure has been investigated using X-ray and neutron diffraction. The hexagonal perovskite structure has an ordered arrangement of Sn and Mn ions on the corner-sharing octahedral centers and the face-sharing octahedral centers respectively. Short Mn-Mn distances have been evidenced in the face-sharing trimer of MnO6 octahedra. The magnetic susceptibility shows magnetic cluster behavior, with cluster formation temperature ∼220 K. Antiferromagnetic order has been observed at T N ∼ 6 K. Ba4Sn1.1Mn2.9O12 is a semiconductor with a transport activation energy of 0.61 eV.
Two new eight-layer hexagonal perovskites with the composition Ba8MNb6O24 (M = Fe and Cu) are synthesized by solid-state reaction at 1350-1400 °C. Their crystal structures have been investigated using X-ray and electron diffractions as well as high-resolution transmission electron microscopy. Although both compounds have similar M2+ size, Ba8FeNb6O24 and Ba8CuNb6O24 adopt shifted and twinned structures, respectively. Through comparison with the reported shifted Ba8MNb6O24 (M = Mn, Co, and Zn) and twinned Ba8NiNb6O24 as well as inexistent Ba8Mg(Nb/Ta)6O24, we elucidate that the twin-shift competition of Ba8MNb6O24 family could be related with multiple chemical factors including tolerance factors, B-cationic size difference, entropy variation with B-cation and vacancy disorder, Jahn-Teller distortion, and FSO B-B d orbit interactions.
New 10H perovskite phases of composition Ba5Ln1−xMn4+yO15−δ (Ln = Sm–Lu) have been synthesised by solid-state reactions at 1300 °C. Their crystal structures have been investigated using X-ray and neutron diffraction. The 10H perovskite structure has an ordered arrangement of Ln and Mn ions on the corner-sharing octahedral centres and the face-sharing octahedral centres respectively. MnO6 octahedral distortions and short Mn–Mn distances have been identified in these structures, and oxygen vacancies are found in the c-BaO3 layers. Additionally, magnetic measurements and neutron diffraction identify spin glass transitions in these new materials. These transitions are related to the Mn ions on the corner sharing octahedral sites, which mediate magnetic interactions between tetramers of MnO6 octahedra.
A new hexagonal perovskite, Ba7Li1.75Mn3.5O15.75, has been synthesised using microwave-assisted solid-state synthesis. Its crystal structure has elements typical for the layered hexagonal perovskites and quasi-one-dimensional oxides, hence representing a new polytype. Structural solution based on simultaneous refinement of X-ray and neutron diffraction data shows that Ba7Li1.75Mn3.5O15.75 crystallizes in a hexagonal unit cell with parameters a = 5.66274(2) Å and c = 16.7467(1) Å (V = 465.063(4) Å3). Columns of face- shared octahedra occupied by Mn4+, Li+ cations and vacancies along the c axis are separated in the ab plane by barium atoms, so that every sixth layer, the coordination of Mn5+ and Li+ changes to tetrahedral. Separation of Mn4+ and Mn5+ cations in two distinct structural positions makes the structure unique. A scanning transmission electron microscopy study revealed the formation of a rhombohedrally centered supercell, which might be attributed to the ordering of manganese and lithium atoms among cationic sites.
Ba7Li1.75Mn3.5O15.75 is a new hexagonal perovskite whose crystal structure has elements typical for the layered hexagonal perovskites and quasi-one-dimensional oxides, hence representing a new polytype. It has been synthesized via a solid-state microwave route. The crystal structure was solved using a combination of X-ray and neutron diffraction data, which show that Ba7Li1.75Mn3.5O15.75 crystallizes in a hexagonal unit cell with parameters a = 5.66274(2) Å and c = 16.7467(1) Å (V = 465.063(4) Å(3)), with one formula unit, and can be described as columns of face-shared octahedra occupied by Mn(4+) and Li(+) cations and vacancies along the c axis separated in the ab plane by barium atoms. Every sixth layer, the coordination of Mn(5+) and Li(+) changes to tetrahedral. Additional local ordering of manganese and lithium atoms among cationic sites leading to the formation of a rhombohedral supercell has been observed by scanning transmission electron microscopy.
