Random field effects at the spin-flop transition of diluted and mixed (K1−<i>x</i>Rb<i>x</i>)2Fe1−<i>y</i>In<i>y</i>(Cl1−<i>z</i>Br<i>z</i>)5⋅H2O

Abstract

The magnetization of the diluted and mixed low anisotropy antiferromagnets (K1−xRbx)2Fe1−yIny(Cl1−zBrz)5H2O was measured as a function of an applied magnetic field 0≤H≤4.0 T in the temperature range 1.5≤T≤15 K. The focus of this work is on the effects that random fields, generated by an external field applied along the easy axis, have on the spin-flop transition. The sharp first order transition that occurs in K2FeCl5H2O has its width increased by almost an order of magnitude when substitution is introduced in any of the K, Fe, or Cl sites. In K2Fe1−yInyCl5H2O and K2Fe(Cl1−zBrz)5H2O hysteseris is also observed. Hysteresis is not observed in (K1−xRbx)2FeCl5H2O.