Coupling between magnetic and thermodynamic properties in RRh_2Si_2 (R = Dy, Ho)

Single crystals of DyRh_2Si_2 and HoRh_2Si_2 were investigated by thermal expansion and magnetostriction. The different types of magnetic order can clearly be seen in these measurements, particularly the canting of the moments away from the crystallographic c direction below about 12 K and the spin-flip for magnetic field applied along the c direction. For HoRh_2Si_2, an additional transition just below T_ N is analyzed by means of the Grüneisen ratio and is likely caused by a change of the magnetic structure. Our results nicely corroborate findings from other magnetic and thermodynamic measurements on these materials and provide further evidence suggesting the formation of magnetic domains.