Magnetic memory effect: Unfolding magnetic metastabilities

This article reviews magnetic memory effects in spin-glasses (SG), superspin-glasses (SSG) and superparamagnetic (SPM) materials with detailed discussions about protocols and mechanisms. The origin of time (t) and temperature (T) dependent magnetic memory effects in different classes of materials have been discussed starting from the nanoscale towards the bulk magnetism. Magnetic memory effects (T and t dependent) in field cooled (FC) and zero field cooled (ZFC) protocols are focused to understand the physics of ageing and rejuvenation in SG, SSG and SPM materials. The article is enlightened with significant discussion to understand the diverse nature and classified properties of magnetic memory of the said materials.