Nuclear magnetic resonance on oriented nuclei in MnBr2.4H2O

Full text: Precision Nuclear Orientation and NMRON studies have been undertaken on the antiferromagnetic insulator (54Mn)MnBr2.4H2O employing the concept of magnetic field induced enhanced nuclear spin-lattice relaxation to obtain working gamma anisotropies as large as -32% (35mK). The results reflect significant differences in detail to those obtained earlier on (54Mn)MnCl2.4H2O. NMRON on (54Mn)MnBr2.4H2O was first obtained by Turrell, however fast magnon cooling was not applied, and so that study was limited to gamma anisotropies of about -5%. In this poster we present, (i) zero field quadrupolar split sub-resonances (m = ±3,±2), (±2,±1) and (±1,0), with the latter two obtained through double and triple resonance techniques, (ii) a two-stage spin flop with the magnetic field aligned along the c-axis, confirming a previous result by Becerra who first observed an intermediate phase between the antiferromagnetic and fully spin flopped phase down to 0.5K using differential magnetic susceptibility, and (iii) NMRON resonances in applied field, thus providing increased accuracy for the nuclear hyperfine parameters