We report the electrical, magnetic, and thermal properties of the delta-FeZn10 phase in the zinc-rich domain of the Fe-Zn system. The delta-FeZn10 phase possesses high structural complexity typical of complex metallic alloys: a giant unit cell comprising 556 atoms, polyhedral atomic order with icosahedrally coordinated environments, fractionally occupied lattice sites, and statistically disordered atomic clusters that introduce intrinsic disorder into the structure. The delta-FeZn10 phase is paramagnetic down to the lowest investigated temperature of 2 K with a significant interspin coupling of antiferromagnetic type.
COBISS.SI-ID: 26035239
Canted antiferromagnetism on a nanodimensional spherical surface geometry was investigated on manganese carbonate MnCO3 small hollow nanospheres of mean diameter 7.0 ± 0.3 nm and shell thickness of 0.7 nm, by performing magnetic measurements and specific heat study, in comparison to the bulk form of the same material. Contrary to the expectation that small magnetic nanoparticles become superparamagnetic, the phase transition to the canted antiferromagnetic (AFM) state in the MnCO3 hollow nanospheres is preserved and retains, at a qualitative level, all the features of the canted AFM state of the bulk material. At a quantitative level, some significant differences between the hollow nanospheres and the bulk were observed, which can all be explained by the weakened interspin interactions in the hollow nanospheres due to reduced atomic coordination by the neighboring atoms. This makes the canted AFM structure of the hollow nanospheres more soft and fragile with respect to external forces like the magnetic field, as compared to the rigid and robust structure of the bulk material.
COBISS.SI-ID: 26336039
Spin-glass properties of magnetic quasicrystals with spins placed on a quasiperiodic lattice, and complex metallic alloys, characterized by giant unit cells, are reviewed. The systems exhibit rich variety of broken-ergodicity phenomena that share properties with site-disordered canonical spin glasses and site-ordered geometrically frustrated antiferromagnets. Magnetic frustration provides basis of a novel concept of digital data storage, where a byte of digital information can be stored into the material by pure thermal manipulation, in the absence of electric, magnetic or electromagnetic field.
COBISS.SI-ID: 25725991