Studies of Weak Electric Quadrupole Interaction In57,60cofe Using Modulated Adiabatic Passage on Oriented Nuclei

The electric quadrupole interactions at57Co and60Co in co-diffused57,60CoFe single crystal have been measured using Modulated Adiabatic Passage on Oriented Nuclei (MAPON). The quadrupole splittings ΔνQ<100> are + 18(2) kHz for57Co and +9(2) kHz for60Co, corresponding to a principal electric field gradient (efg) tensorV zz =2.0(5)×1019 Vm−2 and 2.5(6)×1019 Vm−2, respectively, in broad agreement with previous MAPON results for CoFe. The distributions of the efg’s are very similar for the two isotopes, verifying that previously reported differences in58CoFe and60CoFe could be attributed to different host preparations. The measurement of such weak efg’s which are not spectroscopically resolved, allows determination of new nuclear electric quadrupole moments, not accessible by other techniques. Applications to other systems are discussed.