Magnetic behavior of the two-dimensional antiferromagnet RbFeF4

RbFeF₄ shows anomalous magnetic susceptibility behavior rather similar to that of KFeF₄, in which the existence of two-dimensional antiferromagnetic ordering has recently been clearly demonstrated. A neutron diffraction study of powder samples reveals that RbFeF₄ orders antiferromagnetically in three dimensions at T_N = 134 K. In addition around T_N, the diffraction patterns indicate a magnetic ridge, thus giving, in accordance with KFeF₄, the evidence of the two-dimensional nature of the magnetism in RbFeF₄.