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The nuclear forward scattering (NFS) of synchrotron radiation is especially suited for probing magnetism at very high pressure, here in the Mbar range, by the nuclear resonances of 57Fe and 151Eu. We report on high pressure (h.p.) NFS studies with the 14.4 keV transition of 57Fe on magnetic RFe2 Laves phases of cubic C15 structure (YFe2, GdFe2) and hexagonal C14 structure (ScFe2, TiFe2) at pressures up to 100 GPa (=1 Mbar). We present also h.p. NFS studies performed with the 21.5 keV resonance of 151Eu, probing the magnetism in the CsCl-type h.p. phase of EuTe.

The NMR spin ccho measurements at 4.2 K for YMn2Hx (x=1, 2, 3) compounds are reported. The obtained values of55Mn hyperfine fields are analysed in dependence on the by hydrogen atoms and flips of neighbouring manganese moments. The strong increase of hyperfine field with increasing number of the nearest hydrogen atoms is explained by the change of orbital contribution to hyperfine field.

The x-ray and Mossbauer measurements of both57Fe and161Dy in Dy2Fe17−y Al (y=0, 1,5 and 3) compounds and their hydrides are reported.

The polycrystalline samples of Er2Fe17−xMnx compounds have been studied by57Fe Mossbauer spectroscopy in the temperature range between 4.2K and 200K. A reorientation of the easy axis of magnetization has been evidenced for compound with x=4 in the measurements on magnetically oriented powdered sample. Spin reorientation from the c-axis to the basal plane is observed when temperature is increased above 105K.

The intermetallic compound, YMn12, doped with 0.5at.%57Fe has been investigated using the57Fe Mossbauer resonance. The data show that the Fe impurities occupy preferentially the f-site at the expense of the i- and j-sites. Whereas the i- and j-sites are expected to carry identical local magnetic moments in the ordered state, low temperature hyperfine fields of 50.08(±0.05)T and 2.90(±0.03)T are measured for the i- and j-sites respectively. It is proposed that large transferred hyperfine fields are responsible for this disparity.

The Mossbauer measurements of both57Fe and161Dy in Dy12Fe82B6 system are reported. The presence of B exceeds the magnetic hyperfine fields at both57Fe and161Dy nuclei as compared to corresponding pure metals Fe and Dy respectively. The only small excess of the hyperfine field at57Fe nucleus is observed. The excess at161Dy nucleus is about 12% of the free ion Dy3+ value.

New169Tm Mossbauer and specific heat data recorded for TmCu2Si2 and Tm1/2Lu1/2Cu2Si2 in the temperature range 1.4K to 20K verify that TmCu2Si2 orders magnetically at TN=3K and support earlier conjecture that TmCu2Si2 behaves as a 2-singlet system at low temperatures. However attempts to describe the available data in terms of a single set of parameters suggest that the single-ion and molecular field approximations are an oversimplification of the true situation.