Hello,

You should provide more information.

Dear Simon and Timopheev.

Thanks for your reply

My samples are nano structured thin films. for example, arrays of stair case shaped dots. I am an experimentalist and calculated demag factors by fitting Kittel's formula. But I want to verify the result analytically/theoretically. I know the calculations for rectangular prism, ellipsoid etc. Is there any basic formula for this kind of shapes?

Hi, you can try also the approach of generalized demagnetizing tensor by Newell et al (DOI: 10.1029/93JB00694). This approach is far more general, but in case of ellipsoid shape and homogeneous magnetization the results should be similar to those given by Osborn's equations.

Demagnetization factor is a constant linking magnetization parameter of a ferromagnetic body with the inner demagnetization field arising along the magnetization direction. Such approach is valid then both the demagnetization field and magnetization are uniform in any point of a ferromagnetic body, which is true for an ellipsoid shaped ferromagnet and some limiting cases which can be treated as an ellipsoid (thin film, long rod). In other cases the demagnetization field inside the ferromagnetic body will be nonuniform and can be calculated from the micromagnetic approach. As I understood this is exactly your case.

Alternatively, you can try a simplified case, considering your system a an ellipsoid-shaped body consisting of ellipsoid shaped particles. In this case can you can derive the demagnetization factors for your hierarchically-heterogenous magnetic system (see, for example, R. Skomski, IEEE Trans. Magn., 43 (2007), pp. 2956–2958). I used this approach in this work (http://dx.doi.org/10.1016/j.jmmm.2014.01.029).

Good luck!

For calculation of demagnetization factors, see for example, M.Sato and Y. Ishii, J. Applied Phys., 66, 983 (1989).

Thank you all for the valuable scientific information.

Another classic paper, freely available:

Approximations for the Demagnetizing Factors of Hollow Cylinders Represented by Confocal Hollow Prolate Spheroids

Elfant, R.F.

Electronic Computers, IRE Transactions on

Volume: EC-11 , Issue: 6

Digital Object Identifier: 10.1109/TEC.1962.5219464

Publication Year: 1962 , Page(s): 789

We have formulated simple expressions for computing the demagnetizing factors. The expressions can be used in conjunction with the generalized functions used by Newell.

See Computation of Demagnetization Tensors by Utilizing Fourier Properties

IEEE Transactions on Magnetics 50(11), 10.1109/TMAG.2014.2329703

Article Computation of Demagnetization Tensors by Utilizing Fourier Properties

Note: We have made a small correction to the expressions derived by Newell. Don't use the expressions used by Newell directly.

Hello everyone Where can I find numerical values ​​for demagnetization factors of FeO and MnO using the ellipsoid model?