Paramagnetic Resonance ofNi++,V++

Abstract

The millimeter wave paramagnetic resonance spectra of Ni ++ , V ++ , and Cr +++ have been measured in ZnF 2 . Evidence was found that the extra charge of Cr +++ is compensated by an F~" ion, sitting on one of two available nonequivalent neighboring sites. The antiferromagnetic resonance line in N1F2 which has been postulated by Moriya, is now expected to occur at 320 kMc/sec. T HE paramagnetic spectra of the ions Ni 4-4 ", V+ 4 ", and Cr 44 " 4 " have been measured in the diamagnetic ZnF 2 lattice. They are described by the spin HamiltonianThe parameters for these ions are summarized in Table I. In Ni 44-, V 44 ", and Cr 4 " 4-1 ", spectrum A, the % axis is the [001] axis of ZnF 2 and the x axis follows [110]. In these spectra we do not know the sign of E. In Cr 444-, spectrum B, the z axis is in a (110) plane, 9° off the [110] axis, and the y axis follows the [110] axis.The Cr +++ spectra have previously been measured by Tinkham, 1 but we find 20% smaller zero field splittings than he predicted. We agree, however, with Tinkham's measurement of the directions of the main axes of the spin Hamiltonian, and also with his conclusion that they are due to the presence of an anion which compensates the excess charge on Cr" H_f , and which can occupy either one of two nonequivalent positions. The fact that Cr 44 " 4-can be introduced in considerable amounts, together with recent measurements in CaF 2 2 suggests F~ as the compensating ion.The D term in Ni 4 " 4 " has been predicted by Stout 3 from susceptibility measurements. Moriya 4 has shown, that the Ni 44 " spins are aligned along the [110] axes of 1 M. Tinkham, Proc. Roy. Soc. (London) A236, 535 (1956).

Indirect impurity and host mode excitation via far-infrared level-crossing spectroscopy in antiferromagnets

“…We have found a new excitation in V:FeF2 at 83.0 cm -l at //=0 which is not present in pure FeF2; its absorption intensity is linear 3 in c. Its splitting in a magnetic field yields a g factor (2.03) which is very close to that of V 24 " in ZnF 2 (1.97) 4 and not to that of the host (2.22). Therefore we associate this with the so local mode of a V 2+ impurity.…”

Comparative study of EPR spectra and crystal field effect on local structure for (NiF6)4−coordination complex in Ni2+:ZnF2, NiF2, and Ni2+:MgF2systems

“…Crystals ZnF 2 and MgF 2 doped with Ni 2+ ions are investigated in this paper. Moreover, electron paramagnetic resonance (EPR) spectra and optical spectra of Ni 2+ ions in ZnF 2 :Ni 2+ , NiF 2 , and MgF 2 :Ni 2+ systems have been experimentally observed by many researchers 12–14.…”