Magnetic Properties of Interacting La0.67Sr0.33MnO3 Nanoparticles

Abstract

Magnetic nanoparticles of La 0.67 Sr 0.33 MnO 3 (LSMO) with mean particle sizes of 13, 16, 18, and 21 nm were prepared by the sol-gel method. The samples were characterized by X-ray diffraction (XRD) using Rietveld refinement and transmission electron microscope (TEM). Fourier transform infrared (FTIR) transmission spectroscopy revealed that stretching and bending modes are influenced by annealing temperature. Dc magnetization versus magnetic field of the samples was carried out at room temperature. Magnetic dynamics of the samples was studied by the measurement of ac magnetic susceptibility versus temperature at different frequencies and ac magnetic fields. A frequency-dependent peak was observed in ac magnetic susceptibility versus temperature which is well described by Vogel-Fulcher and critical slowing down laws, and empirical c 1 = T f T f (log 10 f ) and c 2 = T f −T 0 T f parameters. By fitting the experimental data with Vogel-Fulcher magnetic anisotropy energy and an effective magnetic anisotropy constant have been estimated. The obtained values support the presence of strong interaction between magnetic nanoparticles of LSMO.

Dynamic Magnetic Properties of La0.8Ag0.2MnO3 Nanoparticles

“…Using the average particle size of the samples, the effective magnetic anisotropy constants of 1.3 × 10 4 and 2.8 × 10 4 erg/cm 3 are obtained for S1 and S2 samples, respectively. These values are consistent with the values reported for nanoparticles and a single crystal of LSMO (1.8 × 10 4 erg/cm 3 ) [17,19,44]. The existence of a strong interaction between magnetic nanoparticles can lead to a collective superspin glass state.…”

“…The static and dynamic properties of magnetic nanoparticles are strongly dependent on their intrinsic and extrinsic parameters such as saturation magnetization, effective magnetic anisotropy, size and shape of the particles, temperature, and interaction between the particles and the external magnetic field [14,16,17,[19][20][21][22][23][36][37][38][39]. Thermal energy strongly affects the magnetic properties of single domain nanoparticles and causes a superparamagnetic state in an ensemble of magnetic nanoparticles [14,16,17,[19][20][21][22][36][37][38].…”

“…Thermal energy strongly affects the magnetic properties of single domain nanoparticles and causes a superparamagnetic state in an ensemble of magnetic nanoparticles [14,16,17,[19][20][21][22][36][37][38]. In the superparamagnetic state, the magnetization direction of the nanoparticle rapidly fluctuates between easy axis directions.…”

“…Dynamic properties of magnetic nanoparticles are influenced by their intrinsic and extrinsic parameters. In general, the exchange interaction and the magnetic dipolar interparticle interaction play a significant role in the collective behavior of magnetic nanoparticle systems leading to superparamagnetic behavior or a superspin glass state [8,9,11,[14][15][16][17][18][19][20][21][22][23].…”

Structural and Magnetic Properties of Microwave Assisted Sol-Gel Synthesized La0.9Sr0.1MnO3Eshraghi1, Kameli2 2014ISRN NanotechnologySelf Cite2010View full textAdd to dashboardCite

“…The size effects and the large surface area of magnetic nanoparticles intensely change some of the magnetic properties compared to bulk counter parts. Manganite nanoparticles display features like lower values of magnetization [14], higher values of low field magnetoresistance [15], exhibiting superparamagnetic (SPM) phenomena [16], and so forth. SPM nanoparticles with single domain microstructure have a high potential as carriers for biomedical applications.…”