Memory effect and spin-glass-like behavior in Co-Ag granular films

Abstract

The memory effect was clearly observed in dc-sputtered metallic, magnetic Co-Ag granular films, which indicates the existence of a spin-glass-like phase at low temperatures. However, the memory effect diminished dramatically after the films were annealed at 300°C for 1 h. It was also found that the memory effect weakened gradually with increasing volume fraction of magnetic clusters. The experimental results indicate that the dipolar interaction is not the major origin for the formation of low-temperature spin-glass-like ͑SGL͒ phase in metallic, magnetic granular materials. On the other hand, a Ruderman-Kittel-Kasuya-Yosida-like exchange interaction between the nanoparticles may be responsible for the collective SGL dynamics and the resulting memory effect.

Interaction effects in dilute cluster-assembled magnetic nanostructures

“…21,22 This corroborates our picture where it is the clusters themselves that facilitate correlation over longer distances. The difference in magnetic behavior of the two samples of equal concentration shown in Figs.…”

“…Deviations from this simple formalism are due to intra-or intercluster interactions ͑neglecting the quantization of magnetic moment orientation͒ and manifest themselves as "flat-top" GMR curves in postannealed samples. 8,19,20 Magnetic ordering and spin-glass-like behavior have also been observed in rather dilute postannealed granular samples 21,22 but the strongly inhomogeneous concentration and large size distributions make an unambiguous interpretation difficult. We have developed an experimental setup that allows the fabrication of embedded magnetic nanostructures through cluster assembly in a nonmagnetic metallic matrix.…”

Memory and aging effects in antiferromagnetic nanoparticles

“…35 The aging and memory effects are the two aspects that have been studied extensively in recent years, however mostly for the case of ferromagnetic particles. [7][8][9]16,[18][19][20][21][22][23][24][25][26][27] In this paper our aim is to investigate these effects for collection of a few antiferromagnetic nanoparticles (AFNs) which has received relatively lesser attention.…”

Microstructures and the corresponding magnetic properties of half-doped Nd0.5Sr0.5MnO3 films

“…[28][29][30][31] It has been shown that the dipolar interaction plays a very important role for the magnetic properties for SPM ensembles with a sufficiently short distance between granules. Such a type of magnetic material was called the "interacting superparamagnets."…”