Résumé
The magnetic properties of bismuth silicate (BSO) doped with Nd3+, Bi4(1-x)Nd4xSi3O12 (x=0.5%, 1.5%, 2.5%, 3.5%, and 5%) were investigated. X-band electron paramagnetic resonance measurements show that the site symmetry of Nd3+ at 4.2 K is trigonal and the Lande factors were determined to be g(parallel to)=1.15+/-0.01 and g(perpendicular to)=2.47+/-0.02. The exchange coupling between nearest-neighbor (NN) Nd3+ ions was estimated from magnetization measurements, using a model that takes into account the magnetic contributions of single ions and pairs. The exchange interaction between Nd3+ nearest neighbors is antiferromagnetic with an estimated value of J(p)/k(B)=-5.2+/-0.4 K. The energy levels splitting of Nd3+ were obtained from optical absorption spectra measurements at 300, 77, and 5 K.