An unified view of the spin dynamics in two- and three-dimensional magnetic systems
Combining our own experimental results for the temperature dependence of the spontaneous magnetization of ferromagnets and the sublattice magnetization of antiferromagnets with published data for other materials, we propose the following systematics for the exponents describing the decrease of both quantities for finite temperatures: for integer spin quantum numbers and three-dimensional systems for the deviation of both quantities for finite temperatures: for integer spin quantum numbers and three dimensional systems the deviation of both quantities from their T=0 value is given by a T0/2 law but in a two-dimensional systems by a T(2) law. For half-integer spin quantum numbers the exponents are 2 in the 3D casea dn 3/2 in the 2D case. These power laws differ from Bloch's T 3/2 law owing to the presence of fourth-order exchange interactions which re-define the spin dynamics with respect to the situation that only bilinear interactions are active. The observed power laws hold up to temperatures as large as 0.6-0.8 of the critical temperature.
Bibliographic Reference: Article: Journal of Magnetism and Magnetic Materials 205 (1999), 343-356
Record Number: 200011854 / Last updated on: 2000-03-21
Original language: en
Available languages: en