We present results of magnetic measurements performed on TmB12, ErB12, HoB1
2 single - crystalline samples and on a DyB12 poly - crystalline sample in
9.5 mT magnetic field and at temperatures between 1.6 It and 300 K. From th
e observed dependences, which refer to antiferromagnetic ordering in all sa
mples, their Neel temperatures, paramagnetic Curie temperatures, and the ef
fective magnetic moments of the corresponding rare earth ions were determin
ed. The obtained results are compared with values received by other measure
ments.