Proton NMR Study of Random Mixture Fe_1-xMn_xCl₂·2H₂O with Competing Anisotropies and Exchange Interactions

Abstract

Proton NMR measurements of Fe_1-xMn_xCl₂·2H₂O are carried out. In the Mn-type antiferromagnetic phase all spins are parallel to the b-axis which is the easy axis of MnCl₂·2H₂O. In the Fe-type antiferromagnetic phase, for Fe-rich region, all spins are parallel to the α-axis which is the easy axis of FeCl₂·2H₂O, and with increasing Mn concentration some Mn spins tilt from the α-axis. In the “intermediate” phase Fe- or Mn-type (oblique) antiferromagnetic spins coexist with the spin glass spins. All spins lie in the α b-plane with the angle depending on the Mn concentration.