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Author Phan, T.L. ♦ Thanh, T.D. ♦ Phan, M.H. ♦ Yu, S.C.
Sponsorship IEEE Magnetics Society
Source IEEE Xplore Digital Library
Content type Text
Publisher Institute of Electrical and Electronics Engineers, Inc. (IEEE)
File Format PDF
Copyright Year ©1965
Language English
Subject Domain (in DDC) Natural sciences & mathematics ♦ Physics ♦ Electricity & electronics ♦ Technology ♦ Engineering & allied operations ♦ Applied physics
Subject Keyword Frequency modulation ♦ Manganese ♦ Temperature ♦ Magnetic resonance ♦ Temperature dependence ♦ Ions ♦ Saturation magnetization ♦ perovskite manganites and cobaltites ♦ Electron spin resonance (ESR)
Abstract We have prepared two perovskite samples La<sub>0.7</sub>Cd<sub>0.3</sub>MnO<sub>3</sub> (LCMO) and La<sub>0.7</sub>Cd<sub>0.3</sub>CoO<sub>3</sub> (LCCO) by using a solid-state reaction technique and studied their electron spin resonance (ESR) spectra versus temperature up to ~500 K. Experimental results reveal that as compared to LCMO, the resonant signals of LCCO are weaker and easily extinguished by thermal energy. For both samples, there exists a temperature called T<sub>min</sub> at which the narrowest ESR linewidth (ΔH) is obtained. At temperatures , the resonant lines associated with the ferromagnetic phase are asymmetrical. They become a symmetrical single line in the Lorentzian shape when the samples enter the paramagnetic region with T > T<sub>min</sub>. A detailed analysis of resonant spectra in this paramagnetic region reveals that temperature dependences of ΔH can be described by a linear function of the single-phonon process. The resonant intensity versus temperature obeys an exponent function I = I<sub>0</sub> exp(E<sub>a</sub>/k<sub>B</sub>T), where E<sub>a</sub> is the activation energy associated with decomposition of ferromagnetic clusters. Temperature dependences of the resonant position (H<sub>r</sub>) and the Lande factor (g) indicate the dominance of spin-spin and spin-lattice interactions in both LCMO and LCCO, but with the additional presence of the spin-orbit interaction in LCCO at high temperatures (T > 380 K). We believe that the differences in the electronic structure of e<sub>g</sub> and t<sub>g</sub> levels, as well as in the electronic spin configuration of Mn and Co ions, caused the distinct difference in the ESR spectra of LCMO and LCCO.
Description Author affiliation :: Dept. of Phys., Chungbuk Nat. Univ., Cheongju, South Korea
Author affiliation :: Dept. of Phys., Univ. of South Florida, Tampa, FL, USA
ISSN 00189464
Education Level UG and PG
Learning Resource Type Article
Publisher Date 2014-01-01
Publisher Place U.S.A.
Rights Holder Institute of Electrical and Electronics Engineers, Inc. (IEEE)
Volume Number 50
Issue Number 1
Size (in Bytes) 808.66 kB
Page Count 4
Starting Page 1
Ending Page 4

Source: IEEE Xplore Digital Library