NMRON Study of Magnetically Ordered (166m Ho)HoF3

A NMRON study of magnetically ordered HoF₃ using in-situ neutron activated ^166m Ho (I=7) isoelectronic probes in a spherical single crystal is presented. The optimal sensitivity to resonant change in the gamma-ray anisotropy of the 810 keV daughter gamma-ray emission has been utilised to track the lowest nuclear Zeeman substate resonance over an applied magnetic field range from 0.300 to 0.524 T, corresponding to the frequency range 1.56 to 1.78 GHz. The 2nd lowest substate resonance has also been observed at 0.3 T leading to a value P/h=−32.9(14) MHz for the ^166m Ho quadrupolar splitting which is consistent with predictions of a dominant negative pseudo-quadrupole interaction in this system. The Ho³⁺ electronic moment, in zero applied magnetic field, is projected to be 16% smaller than measured previously with neutron diffraction. This revised version was published online in September 2006 with corrections to the Cover Date.