Open Collections

Some applicatins of the quantum theory of magnetism

University of British Columbia

- Part I -The process of the establishment of the equilibrium value of the magnetic moment, when the intensity of the magnetic field is suddenly changed, is discussed for a system of two interacting spins,. First, some of the results obtained by previous writers (Waller, Eisenstein) for the case in which the distance between the two spins remains constant, are summarised. Then, thermal oscillations of the spins are introduced into the calculations, not as such, but as a modification of the equation satisfied by the density matrix of the system. In this way, an expression for the time dependence of the average value of the magnetic moment is obtained, and it is shown that the result includes Eisenstein*s expression as a special case. Its asymptotic value (t-»-oo) is identical with the static value of the magnetic moment corresponding to the new value of the suddenly changed magnetic field. - Part II - A theory, proposed by Opechowski, gives the change of the paramagnetic rotation caused by introducing a high frequency magnetic field perpendicular to the steady magnetic field. To get a more detailed information about this change, the theory was applied to the case of Ni Si F6 6H20, for 9G°K, 9° K and 1.9°K, making reasonable assumptions about the spin-lattice relaxation constant.

Text

2012-02-17

For non-commercial purposes only, such as research, private study and education. Additional conditions apply, see Terms of Use https://open.library.ubc.ca/terms_of_use.

http://hdl.handle.net/2429/40775

Physics

University of British Columbia

Graduate