1. Das A.R., Ananthan V.S., and Khan D.C.: J. Appl. Phys.57 (1985) 4189.
2. Johnson D.W., Callagher P.K., Yan M.F., and Schreiber H., Jr.: Solid State Chem.30 (1979) 299.
3. Baijal J.S., Kothari D., and Phanjoubam S.:in Proc. ICF-5, Bombay (India) 1989 (Eds. Srivastava C.M. and Patni M.J.), Oxford & IBH Publishing Co., PVI Ltd. 1989, Vol. 1, p. 371.
4. Smit J.: Magnetic Properties of Materials, Mc Graw Hill Co., New York, 1971, p. 69.
5. Globus A. and Duplox P.: IEEE Trans.MAG-2 (1966) 441.