Successive magnetic transitions of the pseudo-ternary compounds Ho1R Rh2Si2 (R=Y, La)

Magnetic measurements on the pseudo-ternary compounds Ho 1- x R x Rh 2 Si 2 (R = Y or La = Y or La) were performed in order to get information on the origin of “the successive component-separated magnetic transitions” which appear in HoRh 2 Si 2 . The lattice parameters a and c remain almost constant during changes to Y composition x , while they increase with increasing La composition x . The c / a ratios are also constant in the Y-system, and they increase with increasing x in the La-system especially for above around x = 0.4. The transition temperatures, T N1 = 29.1 K, T t = 27.3 K and T N2 =12.1 K at x = 0, decrease with increasing x . The rates of decrease for T N1 and T N2 in the Y-system accord with those in the La system below x = 0.4. The critical compositions for T N1 and T N2 are determined to be x N1 = 0.88 and x N2 = 0.59 in the La-system, respectively, and x N1 = 0.98 and x N2 = 0.75 in the Y-system. In both the systems, “the successive component-separated magnetic transitions” appear for the wide x regions. The magnetic ordered state persists in very dilute Ho-compounds in spite of much weak magnetic interactions. The effective magnetic moments are almost constant for the ordered compounds; μ eff = 10.6 ± 0.30 μ B /Ho. These behaviors are strange, indicating a strong correlation exists in these systems.