Spin-flop state

Table 2 Evolution of the structural and magnetic characteristics of the [Cp2Mo(dmit)]X salts (X = PF6 , Asly,, Shly, ) with the anion size (BSf stands for the spin-flop field in AF state)...

A three-dimensional set of intermolecular interactions is further confirmed by the observation of a transition to an antiferromagnetic ground state in both radical complexes, at a Neel temperatures of 8 (Mo) and 4.5 K (W), in accordance with the difference of Curie-Weiss temperatures between both complexes. Note also the spin-flop field in the antiferromagnetic state, found at 5.5 kG in [Cp M(dmit)2] and at 8 kG in [Cp W(dmit)2] , a consequence of the stronger spin orbit coupling in the latter. 

The intermediate state in MnF2 in the neighbourhood of the spin-flop transition was studied by means of nuclear magnetic resonance [5] and antiferromagnetic resonance [12], [14]. 

The domain structure, which appears in MnF2 at the spin-flop transition illustrates a general thermodynamic law of intermediate state formation in the process of first-order phase transitions, induced by a magnetic field, and under the condition that the surface energy of the interface boundary (a > 0) is positive. 

A spin-Nuclear spin Fluctuation of A spin quantum state by molecular motion and nuclear spin flip-flop No... 

The spin ices undergo a type of spin flop transition in applied magnetic fields in which the 2 in 2 out ground state is transformed to a 3 in 1 out ... 

Figure 3.23. Magnetic phase diagram of (TMTSF)2Tap6. indicates the spin-flop magnetic field in the AF state).

Electron spin-electron spin interaction. The transition betwen a and P spin states takes place by the interaction between the A spins and the surrounding off-resonant spins (called B spins). The most important process in this type of the relaxation is cross relaxation. In the cross relaxation, the excess energy of the A spin system is resonantly transferred to the surrounding B spins through a flip-flop process. The relaxation rate depends on either the distance betwen the A and B spins or the number of the B spins surrounding an A spin. It is this relaxation mechanism which provides us with a means for studying the local spatial distribution of radical species. 

So unless 71 = 72 an energy difference between these states exists. If the coupled spins are different elements, the B-term in the dipolar Hamiltonian vanishes since the flip-flop process is no longer energy-conserving. Hence the secular dipolar Hamiltonian will change for a set of like-spins and Ij... 

In Equation (2.2), Ii and I2 are the like spins. yi is the gyromagnetic ratio of I nuclei, h is the Plank s constant and r denotes the length of the I1-I2 intemuclear vector. 6 is the angle between the static magnetic field and r. The B-term is called the flip-flop term and causes mutual spin-exchange when the energy levels of the states are very close to each other. Two dipolar precession frequencies in the rotating frame can be obtained from Equation... 

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