Ferromagnetic metals

The values for the atomic saturation magnetization at the absolute zero, Bohr magnetons per atom, respectively.9 These numbers are the average numbers of unpaired electron spins in the metals (the approximation of the g factor to 2 found in gyromagnetic experiments shows that the orbital moment is nearly completely quenched, as in complex ions containing the transition elements). 

Nickel is a ductile, malleable and ferromagnetic metal. Its properties are summarized in Table 6.7. 

This highly conjugated molecule was stabilised with nitroxyl biradical side chains. The resulting material had sufficient ferromagnetism that a usable compass needle could be made from it. Despite the success of this demonstration, organic ferromagnetism remains a curiosity. Such polymers are not likely to replace conventional ferromagnetic metals in any application within the foreseeable future. 

Fig. 8. Schematic representation of a vertical media fabricated by electrodeposition of a ferromagnetic metal into the pores of alumina cells formed by anodization of an Al disk [107]. (Reprinted by permission of The Electrochemical Society).

In their demagnetized states, ferromagnetic metals, such as iron, cobalt, and nickel, consist of randomly magnetized domains separated by well-defined... 

For surface coherent phonons of ferromagnetic metals, a spin-driven generation mechanism was proposed, as will be described in Sect. 2.6. 

Gd(0001) surface, which serves as a model system for a ferromagnetic metal, presented a coherent coupled phonon-magnon mode at 3 THz in the TRSHG measurements, as presented in Sect. 2.6 in the previous chapter. 

An inductor consists of a coil of wire, which may or may not have a core of ferromagnetic metal inside it. A metal core will increase its inductance. 

Nickel is a silver-white, lustrous, hard, malleable, ductile, ferromagnetic metal that is relatively resistant to corrosion and is a fair conductor of heat and electricity. Nickel is a ubiquitous trace metal that occurs in soil, water, air, and in the biosphere. The average content in the earth s crust is about 0.008%. Nickel ore deposits are accumulations of nickel sulfide minerals (mostly pentlandite) and laterites. Nickel exists in five major forms elemental nickel and its alloys inorganic, water-soluble compounds (e.g., nickel chloride, nickel sulfate, and nickel nitrate) inorganic, water-insoluble compounds (e.g., nickel carbonate, nickel sulfide, and nickel oxide) organic, water-insoluble compounds and nickel carbonyl Ni(CO). ... 

Magnetic random-access memory (MRAM) is a new type of computer memory. MRAMs retain their state of magnetization even with the power off, but unlike present forms of nonvolatile memory, they have switching and rewritability rates that challenge (are faster than) those of conventional RAM. In today s read heads as well as those of MRAMs, key features are made of ferromagnetic metallic alloys. Such metal-based devices make up the first—and most mature—of the various categories of spintronics. 

Any paramagnetic (or ferromagnetic) metal complex or particle that decreases the relaxation times of nuclei detected in an image. 

Basic Concepts in Tunneling with Ferromagnetic Metals and Superconductors. 277... 

Fert A, Jaffres H (2001) Conditions for efficient spin injection from a ferromagnetic metal into a semiconductor. Phys Rev B 64 184420... 

Moreover, according to this general schematic mechanism, a more detailed picture of the particle formation has been tentatively given in two particular cases (1) synthesis of colloidal silver particles, and (2) formation of bimetallic ferromagnetic metal particles. 

For a very few metals, however, the unpaired electrons in the conduction band can lead to ferromagnetism. In the whole of the Periodic Table, only iron, cobalt, nickel, and a few of the lanthanides (Gd, Tb) possess this property. So, what is so special about these elements that confers this uniqueness on them It is not their crystal structure they each have different structures and the structures are similar to those of other non-ferromagnetic metals. Iron, cobalt, and nickel, however, all have a nearly full, narrow 3c/band. 

Fig. 13.3. The phase diagram of Ao.33A o.67Mn03 (A = divalent cation, A = rare earth) as a function of temperature and the global instability index of the idealized perovskite structure. The points show the observed transition temperatures in various compounds. FMM = ferromagnetic metal, PMI = paramagnetic insulator, FMI = ferromagnetic insulator (from Rao et al. 1998).

To summarize, we again want to make a sharp distinction between the enhancement in nearly ferromagnetic metals like Ni3Al, where the Stoner enhancement factor can increase x without limit but not dx/dT or y, and the enhancement in nearly antiferromagnetic metals to be discussed in Chapter 4, where x> V and dx/dT are all enhanced. In the former case, all models involve either a non-integral number of electrons in the band or degenerate orbitals. In the latter, two electrons on the same atom necessarily have antiparallel spins. 

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