Atomic Magnetic Moments

Recently it was pointed out by Zener7 that the atomic moments, in parallel orientation, might react with the electrons in the conduction band in such a way as to uncouple some of the pairs, producing a set of conduction electrons occupying individual orbitals, and with spins parallel to the spins of the atomic electrons. Zener assumed that the conduction band for the transition metals is formed by the 4.s orbitals of the atoms, and that there is somewhat less than one conduction electron per atom in iron, cobalt, and nickel. Like Slater, he attributed the atomic magnetic moments to the partially filled 3d subshell. 

Crystal anapole moment is composed of the atomic magnetic moments which array in anapole structure [3]. It has the same intrinsic structure as Majorana neutrino [2], If we plant a p decay atom into this anapole lattice, the crystal anapole moment will couple to the nuclear anapole moment of the decaying nuclei. So the emitted electron will be given an additional pseudoscalar interaction by the presence of the crystal anapole moment. Then the emission probability will be increased. This is a similar process to that assumed by Zel dovich [1], The variation of the decay rate may be measured to tell whether the crystal anapole moment has an effect on the p decay or not. 

For example, let us consider a typical crystal anapole moment of MrnNiN [4], Its anapole moment can be adjusted by temperature. The p source 3H may be permeated into this lattice without destroying the crystal structure. When the temperature is higher than 266K, the atomic magnetic moments of Mn do not array in anapole structure. Then the crystal anapole moment is zero. The p emission probability of 3H is normal. Contributions from other electro-weak processes may be measured at this temperature. When the temperature is lower than 184 K, the atomic magnetic moments of Mn array in the anapole structure and the crystal present anapole moment to the 3H nuclei. Then the electron s emission rate of 3H will be increased. 

Transitions from a localized to an itinerant state of an unfilled shell are not a special property of actinides they can, for instance, be induced by pressure as they rue in Ce and in other lanthanides or heavy actinides under pressure (see Chap. C). The uniqueness for the actinide metals series lies in the fact that the transition occurs naturally almost as a pure consequence of the increase of the magnetic moment due to unpaired spins, which is maximum at the half-filled shell. The concept has resulted in re-writing the Periodic Chart in such a way as to make the onset of an atomic magnetic moment the ordering rule (see Fig. 1 of Chap. E). Whether the spin-polarisation model is the only way to explain the transition remains an open question. In a very recent article by Harrison an Ander-... 

Five oxidation states of iron, II-VI, are accessible in oxides. The principal oxidation states are II-IV these all carry spontaneous atomic magnetic moments in oxides the mixed-valence states of particular interest are associated with III/II and IV/III couples on crystallographically equivalent sites. The low-temperature disproportionation reaction 2 Fe — Fe Fe " in CaFe03 is also of fundamental theoretical interest. 

Values of the low-temperature saturation magnetic moment of ferromagnetic substances represent the maximum component of the atomic magnetic moment in the field direction for example, for spin alone the value in Bohr magnetons is 2S, whereas the magnetic moment obtained from the paramagnetic susceptibility is 2 /S(S + 1). 

Average magnetic moment per nickel(U) atom. Magnetic moment referred to the dimetallic complex. 

The basic concept of micromagnetism is to replace the atomic magnetic moments by a continuous function of position. In a continuum theory the local direction of the magnetic moments may be described by the magnetic polarization vector... 

L. Pauling, Electron transfer and atomic magnetic moments in the ordered intermetallic compound AlFe3- in Quantum Theory of Atoms, Molecules, and the Solid State, P.-O. Lowdin, ed., Academic Press, New York, 1966, pp. 303-306. 

A macroscopic sample (which need not be a bar magnet or current-carrying coil), comprised of a very large number of microscopic (atomic) magnetic moments, can be defined as the magnetization, M, as the net magnetic moment per unit volume (SI units A/m, gauss/cm, or emu/cm in the cgs system) ... 

There has been a considerable effort in the physics and chemistry communities to use INS methods to study magnetic dynamics, which can often be described as spin waves. Measurements of spin wave dispersion curves can provide information about the interactions between atomic magnetic moments, the so-called exchange interactions. There have been comparatively few INS measurements on magnetic minerals. INS methods have been used to produce spin wave dispersion curves for hematite. Crystal field magnetic transitions in cobalt bearing cordierite, and spinel phases have also been studied by INS. ... 

A second challenge is in the understanding of surface magnetism elementary spin-spin interactions, atomic magnetic moments on surface sites, collective properties such as surface magnetic ordering, spin polarised transport across oxide ultra-thin barriers, etc. We have not developed this problematics here, because, until now, there have been very few related the-... 

E.LDashevskaya and E.E.Nikitin, Classical dynamics of atomic magnetic moment for quadratic interaction with an external magnetic field, Khim. Fiz. 5,457 (1986)... 

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