Electron spin, parallel, aligning

Two theories were introduced in the 1960s on how to align electron spins in parallel between open-shell molecules (McConnell, 1963, 1967). 

A Guiding Principle on Aligning Electron Spins in Parallel between IWo Neighboring Molecules... 

Figure 3 shows the calculated conductivity for one of the channels when the cobalt moments on either side of the copper layer are aligned anti-parallel. The spin channel for which the conductivity is shown in Figure 3 is locally the majority channel in the cobalt layer to the left of the copper (spin parallel to the Co moment) and locally minority to the right of the copper (electron spin anti-parallel to the local Co moments). The non-local conductivity for the other spin channel for the case in which the cobalt moments are antiparallel is the mirror image of the conductivity shown in Figure 3. 

Polymer that exhibits magnetic properties because it has unpaired electron spins aligned parallel to each other or electron spins that can easily be so aligned. 

Observation of ESR from a particular sample is contingent upon the presence of a macroscopic spin magnetic moment jZ i.e., die sample under investigation must contain some minimum number of unpaired electron spins. Upon insertion into the cavity, the sample is subjected to the dc magnetic field H, and the unpaired electrons align themselves both parallel... 

In the absence of further limit conditions which may hold in the case of the electron (see later), we can now think of an electron spin and a nuclear spin anchored at points A and B, both aligned along the external magnetic field Bo, as shown in Fig. 1.5. Since the two magnetic moments are forced to be parallel by the strong external field, the energy of the interaction between them, given by Eq. (1.1), simplifies to... 

With increasing atomic volume, one approaches the free atom limit where Hund s first rule postulates maximum spin, so that the individual spins of the electrons in a shell are aligned parallel. More generally, Pauli s exclusion principle implies that electrons with parallel spins have different spatial wavefunctions, reduces the Coulomb repulsion and is seen as exchange interaction. When the atoms are squeezed into a solid, some of the electrons are forced into common spatial wavefunctions, with antiparallel spins and reduction of the overall magnetic moment. At surfaces and interfaces, the reduced coordination reverses this effect, and a part of the atomic moment is recovered. 

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