Electric charge transport anomalies in holmium and thulium thin films at low temperatures * ) J. Dud´ aˇ s, M. Guzan Department of Theoretical Electrotechnics and Electrical Measurement, Technical University of Koˇ sice, Park Komensk´ eho 3, SK–043 89 Koˇ sice, Slovakia S. Gab´ ani, V. Kaveˇ cansk´ y, K. Flachbart Institute of Experimental Physics SAS, Watsonova 47, 043 53 Koˇ sice, Slovakia M. Konˇ c Institute of Physics, Faculty of Science, P. J. ˇ Saf´arik University, Park Angelinum 9, 041 54 Koˇ sice, Slovakia I. Go` scia` nska Institute of Physics, A. Mickiewicz University, Umultowska 85, 61-614 Pozna` n, Poland Received 4 May 2004; final version 21 June 2004 High-precision electrical resistance measurements were performed on holmium and thulium bulk and thin-film samples in the temperature range from 4.2 K up to room temperature. A “knee-like” resistance anomaly near the N´ eel temperature was observed in Ho bulk and thin-film samples. The X-ray diffraction of Ho films revealed diffraction peaks coming from the h.c.p. structure of Ho and those from holmium dihydride. Unexpected resistance anomalies were observed for thulium thin films in the temperature region below ≈ 60 K and near ≈ 170 K. The crystal structure study revealed diffraction peaks originating only from the Tm h.c.p. crystal structure. PACS : 61.10.Nz, 68.55.Jk, 72.15.Eb, 73.61.At Key words : Electrical resistance, holmium and thulium thin films, low temperatures 1 Introduction Transport and magnetic properties of magnetic metallic thin films exhibit a new and considerable renascence since the discovery of spin polarized transport in mul- tilayered ferromagnetic/nonmagnetic structures. The discovery of giant magnetore- sistance (GMR) and tunnelling magnetoresistance has strongly stimulated study of arrays of magnetic films – see e.g. [1, 2]. The effect of GMR was originally observed in Fe/Cr multilayers, later with Co and Ni as ferromagnetic films, and with various nonmagnetic spacers like Au, Ag, Cu. As for rare-earth metal thin films, magne- toresistance was studied in multilayers with CoSm layers [3], GdCo films [4] and positive GMR was observed in Dy/Sc superlattices [5]. * ) Presented at 12-th Czech and Slovak Conference on Magnetism, Koˇ sice, 12-15 July 2004 Czechoslovak Journal of Physics, Vol. 54 (2004), Suppl. D D253