Ferromagnetic compounds

Zener, C. 1951. Interaction between the (/-shells in the transition metals. II. Ferromagnetic compounds of manganese with perovskite structure. Physical Review 82 403-405. 

Table 5.7. Ferromagnetic compounds with the ordered perovskite structure.

The critical temperature (Tc) where Prussian Blue nanoparticles turn to a ferromagnetic compound was found to be 5.1 K that is slightly less then the value for the bulk PB (5.5 K). This result is qualitatively consistent with... 

Table 3. Magnetic data of A2CuF4 ferromagnetic compounds...

TTFs, also named 2,2 -bi-l,3-dithiole, 2,2 -bi-(l,3-dithiolylidene), are one of the most studied systems in the field of molecular materials because of their ability to participate in electrically conducting and superconducting cation radical salts or CT complexes. The utility of TTF derivatives as building blocks in macromolecular and super-molecular structures, molecular-based ferromagnetic compounds, donor moieties in intramolecular D-A systems in... 

On the other hand, alternate stacks will generally lead to insulating materials. As will be seen later, it is this type of structure that afforded ferri- and ferromagnetic compounds. 

A ferromagnetic material consists of magnetically ordered domains separated by transition zones, the so-called Bloch walls (ca 30 nm). In finely divided ferromagnetic compounds, with size less than this critical value, particles consist of magnetic sing. e domains, At temperature T, they may exhibit a kind of Brownian movement, affecting the orientation of the magnetic moment p of the particle considered as a whole (p = Npo N,... 

NajO, CaO), through semiconductors (VO2), to metallic conductors (Cr02, RUO2). Binary oxides also include two of the rare examples of ferromagnetic compounds, EuO and Cr02. 

The FMR technique presents the same advantages as EPR in situ experiments are possible on minute quantities of samples that are not destroyed. The interpretation of the spectra is, however, rather involved and the method is limited to ferromagnetic compounds containing essentially Fe, Co, Ni, or their alloys. 

The first group are the ferromagnetic compounds of U and Np with d transition metals. Except for UNi2, UPt, and NpOs2 the magnetism in these materials is predominantly of 3d origin. The direct 5f-5f overlap and the 5f-d hybridization prevent the 5f electrons from a distinct localization also in these three compounds,... 

These are obtained by dispersion of one or more solid fillers in a binder. The binder should be either inorganic (silica based ceramic) or organic (thermosetting or thermoplastic polymers) depending on the environmental conditions. Fillers are composed of ferrite described above with granulometry comprised between 12 and 100 pm and also of simple ferromagnetic compounds (Fe, Co, Ni) or complex alloys. 

Rode et al. (107) carried out an electron spin resonance study of the intermediate oxides formed in the thermal decomposition of chromic anhydride. Chromium decachromate, chromium dichromate, and chromium hydroxide at room temperature, as well as the ferromagnetic compounds chromium monochromate and chromium dioxide above their Curie points at 130°, give symmetrical absorption lines 130 to 160 gauss wide with a g factor of 1.97, Shnkin and Fedorovskaia (108) studied CrgOa containing lithium, and detected fine structure in the ESR spectrum. 

Braun, P. B. (1957). The crystal structure of a new group of ferromagnetic compounds. Philips Research Reports, 12, 491-548. 

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