Effect of strontium substitution on the structural and magnetic properties of La_1.8Sr_0.2MMnO₆ (M = Ni, Co)-layered manganites

ABSTRACT

Sr-substituted perovskites, La_1.8Sr_0.2MMnO₆ (M = Ni, Co), were synthesized using the solid-state reaction technique to present a systematic study on their morphological, structural and magnetic properties. The average grain size of the as-prepared La_1.8Sr_0.2NiMnO₆ samples are in the range of 0.2–0.7 µm and those for La_1.8Sr_0.2CoMnO₆ manganites are 0.1–2.8 μm, which is significantly less than that of unsubstituted La₂NiMnO₆ (LNMO) and La₂CoMnO₆ (LCMO) manganites. The XPS analysis enlightened about phase purity, binding energy and oxygen vacancy of La_1.8Sr_0.2MMnO₆ manganites. The Sr-substituted LNMO has revealed a sharp ferromagnetic to paramagnetic phase transition at 160 ± 2 K, which is about 120 K less than that of parent LNMO. The Sr-substituted LCMO exhibited such a transition at 220 ± 2 K, which is 8 K less than that of parent LCMO. The temperature-dependent magnetization measurements suggest that the effect of Sr on the transition temperature in LNMO is more significant than that of LCMO.

KEYWORDS:

• Layered manganites
• XPS analysis
• magnetization
• magnetic transition

Acknowledgments

The magnetization measurements using SQUID were conducted in the Institute for Molecular Science (IMS), supported by Nanotechnology Platform Program (Molecule and Material Synthesis) of the Ministry of Education, Culture, Sports, Science and Technology (MEXT), Japan.

Disclosure statement

No potential conflict of interest was reported by the authors.

Additional information

Funding

The Ministry of Science and Technology, Government of Bangladesh [grant number: 39.009.002.01.00.053.2014-2015/PHY'S-273/(26.01.2015)].