Features of magnetic and thermal properties of R(Co1−xFex)2 (х≤0.16) quasibinary compounds with R=Dy, Ho, Er

•Magnetic and magnetocaloric properties of R(Co–Fe)2 compounds have been studied.•Fe introduction induces the disorientation effect in Ho-ions magnetic ordering.•Emergence of magnetic contribution to a heat capacity at temperatures less TC.•The existence of a broad maximum on a temperature dependence of the MCE.•Direct MCE measurements at magnetic field of (0–17.5) kOe have been performed.

In this work the results of measurements of high field susceptibility, paraprocess susceptibility and thermal properties of R(Co1−хFeх)2 intermetallic compounds (R=Dy, Ho, Er and x=(0−0.16)) are presented (heat capacity and magnetocaloric effect (MCE)). A magnetic structure of the Ho(Co0.88Fe0.12)2 at 293 K and 78 K was studied by neutron powder diffraction. Some peculiarities of a high-field susceptibility were revealed at low temperatures and around the Curie point (TC). In temperature range lower than TC by (100–150) K, magnetic contributions to a zero-field heat capacity were found. Studying MCE in wide temperatures range, the large change of the entropy magnetic contribution (∆S) was observed which correlates with ∆T phenomenon. In particular, for the Er(Co0.84Fe0.16)2 compound the ∆S value at low temperatures is six times higher than that at Curie point. The possible reasons of such behavior were discussed.