Title :
Electron Spin Resonance Study on Room-Temperature Ferromagnetic La0.9Sr0.1MnO3 Nanoparticles
Author :
Chen, Y.S. ; Liang, K.L. ; Chang, C.C. ; Lin, J.G.
Author_Institution :
Center for Condensed Matter Sci., Nat. Taiwan Univ., Taipei, Taiwan
Abstract :
Temperature-dependent electron spin resonance (ESR) is applied to investigate La0.9Sr0.1MnO3 nanoparticles incorporating with magnetization and electrical transport measurements. Ferromagnetism is observed at room temperature which is much higher than the TC value for bulk samples (~150 K). The ESR analysis confirms the coexistence of multiple magnetic phases consistent with the field-dependent magnetization-temperature curves. By fitting ESR spectra, the room-temperature multiphases are identified as the mixture of ferromagnetic and paramagnetic states, similar to the Griffiths phase observed in bulk samples. The field-dependent resistivity shows colossal magnetoresistance effect up to room temperature. Based on our analysis, the size-effect-induced room-temperature ferromagnetism is strongly correlated with the enhancement of the Griffith phase separation temperature.
Keywords :
colossal magnetoresistance; ferromagnetic materials; lanthanum compounds; magnetic particles; magnetisation; nanomagnetics; nanoparticles; paramagnetic materials; paramagnetic resonance; phase separation; strontium compounds; ESR spectra; Griffith phase separation temperature; La0.9Sr0.1MnO3; colossal magnetoresistance effect; electrical transport measurements; ferromagnetic nanoparticles; ferromagnetic states; ferromagnetism; field-dependent magnetization-temperature curves; field-dependent resistivity; magnetization; multiple magnetic phases; paramagnetic states; temperature 293 K to 298 K; temperature-dependent electron spin resonance; Electric variables measurement; Frequency modulation; Magnetic resonance; Magnetic separation; Magnetization; Nanoparticles; Temperature measurement; Colossal magnetoresistance; Magnetic resonance; Nanoparticles;
Journal_Title :
Magnetics, IEEE Transactions on
DOI :
10.1109/TMAG.2015.2438094