Revival of Metal-Insulator and Ferromagnetic-Paramagnetic Transitions by Ni Substitution at Mn Site in Charge-Ordered Monovalent Doped Nd{sub 0.75}Na{sub 0.25}MnO{sub 3} Manganites
Nd{sub 0.75}Na{sub 0.25}Mn{sub 1−x}Ni{sub x}O{sub 3} (x = 0 − 0.07) were synthesized using a conventional solid-state synthesis method to investigate the effect of Ni substitution on their magnetic and electrical transport properties. XRD analysis using the Rietvield refinement method showed an increase in unit cell volume with increasing Ni content, indicating the possibility of substituting Ni for the Mn site. For x = 0, magnetization measurements showed paramagnetic (PM) to antiferromagnetic (AFM) transition at the transition temperature, T{sub N} ∼ 185 K, which may be related to the presence of charge-ordering (CO) state. For Ni-substituted samples, ferromagnetic (FM) to PM transition was induced with Curie temperature (T{sub C}), increasing from 91 K (x = 0.01) to 115 K (x = 0.03), followed by decreases in T{sub C} to 60 K (x = 0.07). Electrical resistivity measurements showed that samples for x ≤ 0.01 exhibited insulator behavior while both x = 0.03 and 0.05 samples exhibited metal-insulator transition suggesting that the CO state is weakened. For x = 0.07, the sample shows re-entrant of insulating characteristic. Inducement of FM metallic (FMM) state, as well as increased of T{sub C} for x = 0.03 is suggested to be related to FM SE between Ni{sup 2+} and Mn{sup 4+}, which suppressed the CO state, hence inducing double-exchange (DE)-like mechanism. In addition, an increase in resistivity was observed as temperature decreased below the resistivity minimum (R{sub min}) at T{sub min} ∼ 40 K for x = 0.05 is possibly due to the Kondo-like effect mechanism. On one hand, the M(H) curve showed the presence of a hysteresis loop for x = 0 and 0.01 at T= 60 and 80 K, indicating the presence of an unstable phase, which may be related with the CO-AFM phase. For x = 0.03, no hysteresis loop was observed, indicating the suppression of the CO-AFM. Intriguingly, for x = 0.05 and 0.07, small hysteresis loop was observed, indicating the possible presence of a minor AFM component. Further, the observed MR behavior in present studies can be understood as a result of a decreased scattering mechanism in the presence of magnetic field.
- OSTI ID:
- 22773822
- Journal Information:
- Journal of Superconductivity and Novel Magnetism, Vol. 31, Issue 9; Other Information: Copyright (c) 2018 Springer Science+Business Media, LLC, part of Springer Nature; http://www.springer-ny.com; Country of input: International Atomic Energy Agency (IAEA); ISSN 1557-1939
- Country of Publication:
- United States
- Language:
- English
Similar Records
Non-Fermi-liquid types of behavior associated with a magnetic quantum critical point in single crystals
Magnetic properties of pseudo-ideal cubic La{sub 0.6−x}Ca{sub x}Ba{sub 0.4}CoO{sub 3} with hole doping