Theories of the Differential-Thermal-Resp. Magneto-Thermal-Analysis. A Detailed Description of the Two Apparatus and of Further Measurements on Re-Mn-Alloys

摘要

An apparatus for measurements on small samples (0,5 1 g) of high reactive RE-alloys (RE-Hg, RE-Mn alloys etc.) was developed. It consists of a platinum-wire furnace, a sample holder with crucibles (made of tantalum), an electronic temperature regulation and a recorder. The possibilities of this device are discussed. A magnetic balance is described, which allows measurements on REalloys from 80K to 1400K. Measurements on GdMn2, GdMn5 and GdMn12 between 80K and 1370K showed that GdMn2 becomes antiferromagnetic at 86K and that GdMn5 is not ferromagnetic but ferrimagnetic (T sub C = 465K). The results are discussed in terms of the theory of Neel. The number of Bohr-magnetons, gained from the measurements at high temperatures (in the paramagnetic region) are compared with theory.