کد مقاله | کد نشریه | سال انتشار | مقاله انگلیسی | نسخه تمام متن |
---|---|---|---|---|
7990667 | 1516130 | 2018 | 8 صفحه PDF | دانلود رایگان |
عنوان انگلیسی مقاله ISI
Tuning ferromagnetism and spin state in La(1âx)AxCoO3 (A= Sr, Ca) nanoparticles
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کلمات کلیدی
موضوعات مرتبط
مهندسی و علوم پایه
مهندسی مواد
فلزات و آلیاژها
پیش نمایش صفحه اول مقاله
چکیده انگلیسی
We investigate the structural, magnetic susceptibility, isothermal magnetization, and electronic properties of La(1âx)AxCoO3 (A= Sr, Ca; x= 0-0.2) nanoparticles. The Rietveld refinement of room temperature powder x-ray diffraction data shows that all the samples crystallize in the rhombohedral structure (space group R3¯c). We observe a significant increase in the ferromagnetic transition temperature as well as in the spontaneous magnetic moment with Sr/Ca substitution at the La site. Interestingly, the coercive field HC decreases/increases with Sr/Ca substitution [4.4 and 13.2â¯kOe for x= 0.2 (Sr) and 0.2 (Ca) samples, respectively] as compared to the x= 0 sample (7â¯kOe). X-ray photoemission spectra of core-levels confirm the oxidation state of the constituent elements. Moreover, we demonstrate that the Sr/Ca substitution increases the population of intermediate-spin (IS) and low-spin (LS) states of Co3+ and Co4+ ions, respectively; which tune the ferromagnetism in nanoparticles via double-exchange interaction. More importantly, the contribution of IS states of Co3+ ions and induced strain are significantly larger in Sr substituted samples than in Ca samples, which favours the interpretation of a Jahn-Teller distortion in the Sr samples. This is consistent as in contrast to Ca samples, the magnetic behavior of La(1âx)SrxCoO3 nanoparticles is significantly different than the counterpart bulk samples having same substitution level. Our results suggest the important role of hole carriers, induced strain and nano-size effect in tuning the spin-state and magnetism in La(1âx)AxCoO3 nanoparticles.
ناشر
Database: Elsevier - ScienceDirect (ساینس دایرکت)
Journal: Journal of Alloys and Compounds - Volume 764, 5 October 2018, Pages 379-386
Journal: Journal of Alloys and Compounds - Volume 764, 5 October 2018, Pages 379-386
نویسندگان
Ravi Prakash, Rishabh Shukla, Priyanka Nehla, Anita Dhaka, R.S. Dhaka,