139La NMR study of RE2Fe14B compounds (RE = La,Nd,Y)

Abstract

The 139La NMR spin-echo spectra of La2Fe14B, La0.2Nd1.8Fe14B, La0.2Y1.8Fe14B and La0.1Y1.9Fe14B at 4.2 K are reported. The values of the lattice electric field gradient at the rare earth sites 4f and 4g correspond to a difference of the crystal electric field coefficients A20 by a factor of 2 between those sites. In La0.1Y1.9Fe14B the occupancy of lanthanum on the 4g sites is found to exceed that on the 4f sites by a factor of 4.