Magnetic moment per

Figure Cl.1.5. Nickel cluster magnetic moment per atom (p) as a function of cluster size, at temperatures between 73 and 198 K. Apsel S E, Emmert J W, Deng J and Bloomfield L A 1996 Phys. Rev. Lett. 76 1441, figure 1.

The saturation magnetization, J), is the (maximum) magnetic moment per unit of volume. It is easily derived from the spia configuration of the sublattices eight ionic moments and, hence, 40 ]1 per unit cell, which corresponds to = 668 mT at 0 K. This was the first experimental evidence for the Gorter model (66). The temperature dependence of J) (Fig. 7) is remarkable the — T curve is much less rounded than the usual BdUouia function (4). This results ia a relatively low J) value at RT (Table 2) and a relatively high (—0.2%/° C) temperature coefficient of J). By means of Mitssbauer spectroscopy, the temperature dependence of the separate sublattice contributions has been determined (68). It appears that the 12k sublattice is responsible for the unusual temperature dependence of the overall J). 

The muffin-tin potential around each atom in the unit cell has been calculated in the framework of the Local-Spin-Density-Approximation using the ASW method. The ASW method uses the atomic sphere approximation (ASA), i.e. for each atom a sphere radius is chosen such that the sum of the volumes of all the overlapping spheres equals the unit cell volume. The calculation yields the expected ferromagnetic coupling between Cr and Ni. From the self-consistent spin polarized DOS, partial and total magnetic moment per formula unit can be computed. The calculated total magnetic moment is 5.2 pg in agreement with the experimental value (5.3 0.1 e calculations presented here have been performed... 

Figure 1 Experimental magnetic moments per atom of Ni, Co and Fe clusters with sizes up to 700 atoms. Reproduced with permission from Ref. 2.

Table 1. Calculated Average Bond Distance d, Number of Bonds Per Atom NB, Magnetic Moment Per Atom p, Binding Energy Per Atom Eb, and Spin Gaps Ai and A2 of Mnw Clusters.93... 

Table 2. Binding Energy Per Atom Eb, Distance D from Atoms to the Cluster Center, and Average Magnetic Moment Per Atom p for Octahedral Six-Atom Clusters. Data Collected from Zhang et al.107... 

The thermally averaged electronic magnetic moment per molecule, induced by the external magnetic field, can in a general anisotropic case be... 

The behavior of the magnetic susceptibility as a function of temperature is in accord with what one should expect from an array of small isolated metal clusters, with splitting between the filled and the empty intra-cluster electronic energy bands of the order of 30 K. The magnetic moment per cluster of less than one electron spin still requires clarification. 

Recall that the saturation magnetization, Mj, is the maximum possible magnetization in the material, and is simply the prodnct of the net magnetic moment per atom. Pm, and the number of atoms per unit volnme, N. The net magnetic moment, in turn, is related to the electronic structure (paired or unpaired electrons), although a number of other factors come into play. Use this information to calculate the saturation magnetization for nickel. 

Person 1 Calculate the net magnetic moment per unit cell for copper ferrite. Remember that there is more than one formula unit (CuFe204) per unit cell in the inverse spinel structure. 

When a substance is placed in a magnetic field H, it develops a certain amount of magnetization (magnetic moment per unit volume) M given by M = yH, where y is the magnetic susceptibility. The magnetic induction B is defined as... 

Magnetism is an intrinsic property of all materials. When placed in a magnetic field, H, a substance develops an amount of magnetization, M (magnetic moment per unit volume), given by ... 

It is implied in Eq. (38) that, at temperature 0, the value of susceptibility becomes infinite and that there is a finite value of the magnetic moment per unit volume (see Eq. 36), even in the absence of an external field (H = 0) at temperatures lower than 0. Below 0 (a characteristic temperature for a given substance), atom and dipoles (spins) of magnetic materials are ordered. 

Fig. 11-1.—Observed values of saturation magnetic moments per atom of transition elements of the iron group and their alloys. Values for some alloys, which deviate from the curve, are not shown these alloys probably involve ferrimagnetism.

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

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