B. Verkin Institute for Low Temperature Physics and Engineering of the National Academy of Sciences of Ukraine 47 Nauky Ave., Kharkiv 61103, Ukraine
V.V. Mal’tsev, N.N. Kuzmin, and N.I. Leonyuk
Lomonosov Moscow State University, 1 Leninskie Gory, Moscow 119991, Russia
Received December 19, 2017
The temperature dependence of single crystal magnetic susceptibility χ(Т) of GdCr3(BO3)4 in the temperature range 2–300 K for two orientations of external magnetic field Н || c and Н ⊥ c has been investigated. It is established that the gadolinium chromium borate is ordered antiferromagnetically at ТN = 7 K. It is found that at Т > 10 K the magnetic properties are isotropic, that is characteristic of pure spin states of the Cr3+ and Gd3+ ions. It is shown that at Т > ТN the magnetic susceptibility χ(Т) of GdCr3(BO3)4 is well described by using an one-dimensional spin model for a system of the coupled chains of the Cr3+ ions with ferromagnetic intrachain exchange 2J/k = –13,6 K and antiferromagnetic interchain interaction of 2J′/k = +0,72 K. In addition, the paramagnetic gadolinium subsystem has the antiferromagnetic spin-spin correlations thanks to the exchange f–d interaction, which gives θGd = –2,8 K. It is suggested that in the magnetically ordered state the GdCr3(BO3)4 compound is an antiferromagnet with an easy-plane anisotropy.