Dynamic properties of cluster glass in La0.25Ca0.75MnO3 nanoparticles

Abstract

The dynamic magnetic properties of cluster glass in La0.25Ca0.75MnO3 nanoparticles with average particle size range from 40 to 1000 nm have been investigated by measuring the frequency and dc magnetic field (H) dependencies of the ac susceptibility. The frequency-dependent Tf, the freezing temperature of the ferromagnetic clusters determined by the peak in the real part of the ac susceptibility χ′ versus T curve with H=0, is fit to a power law. The relaxation time constant τ0 decreases as the particle size increases from 40 to 350 nm, which indicates the decrease in the size of the clusters at the surface of the nanoparticle. The relationship between H and Tf(H) deviates from the De Almeida–Thouless-type phase boundary at relatively high fields for the samples with size range from 40 to 350 nm. Moreover, for the samples with particle sizes of 40 and 100 nm, τ0 increases with increasing H, which indicates the increasing cluster size and may be ascribed to the competition between the influence of H and the local anisotropy field in the shell spins. All these results may give rise to a new insight into the behaviors of the cluster glass state in the nanosized antiferromagnetic charge-ordered perovskite manganites.

A-site ion-size effect on the transport and magnetic properties of Ce doping Pr0.3Ce0.2CaxSr0.5−xMnO3 (0≤x≤0.25)

“…4, it can be found that there are bifurcations between the zero-field-cooled (ZFC) and the fieldcooled (FC) curves, which correspond to the appearance of a short-range FM coupling and the formation of FM clusters. [29][30][31][32] We suggest that the short-range magnetic orders of Ce 3þ appear in the samples due to the formations of the short-range FM coupling and the FM clusters of Mn ions. To further confirm the onset of magnetic ordering of Ce 3þ , the ESR spectra of the samples are investigated.…”

Interfacial Spin Glass State and Exchange Bias in the Epitaxial La0.7Sr0.3MnO3/LaNiO3 Bilayer

“…The irreversibility temperature ( T irr ) also appears to be a bifurcation between the ZFC and FC curves. Based on these phenomena, we analyze the result usually observed for the several commonly known magnetic systems, such as spin glass [22, 23], spin clusters [24, 25], and superparamagnets [26]. Here, T P and T irr are very close to each other for all applied magnetic fields, and T P shifts to low temperatures quickly as the measurement field increases.…”

Effect of Pr doping on the properties of Bi0.5−xPrxCa0.5MnO3 (0≤x≤0.50) manganites

“…9 for x = 0.40 sample) could be due to increase in FM-DE interactions as temperature decreases. A sharp rise in M observed below 45 K for x = 0 and below 115 K for x ≥ 0.05 samples is indicative of FM-cluster glass (CG) formation [43]. Below this temperature, M (ZFC) shows a peak at a temperature known as spin freezing temperature (T f ) [16], while M (FC) (except for x = 0.20) increases continuously with decrease in temperature.…”