title: Ti8(Ti(x)Mn(1-x))6Mn39 ('TiMn(~4)'): a metallic spin fluctuation system.
abstract: The crystal structure of Ti(8)(Ti(x)Mn(1-x))(6)Mn(39), x = 0.187, was obtained from x-ray single-crystal diffraction data, confirming it to have rhombohedral symmetry (space group [Formula: see text]; a(hex) = 1.100 70(2) nm, c(hex) = 1.944 11(4) nm; R(F) = 0.0293) and isotypism with the prototype Mo(0.38)Cr(0.16)Co(0.46) (the so-called R-phase). On the basis of electron probe micro-analyser results and structure determination, the homogeneity region of the phase TiMn(~4) was determined for temperatures in the range 800 °C < T < 1200 °C and is in between 16.0 at.% Ti and 20 at.% Ti. Various physical properties, determined in the temperature range from ~2 K to room temperature, characterize the compound with composition TiMn(4.26) as a metallic spin fluctuation system, evidenced from a T(3)lnT dependence of the heat capacity in combination with large values of the electronic Sommerfeld constant of the order of 140 mJ mol(-1) K(-2). The occurrence of a small anomaly in the heat capacity and magnetization data around 10 K is attributed to a scenario involving spin freezing phenomena, since a fraction of the order of 10% of all Mn-Mn distances within the unit cell are above a critical distance, where Mn atoms carry a spontaneous magnetic moment.
authors: Institute of Physical Chemistry, University of Vienna, Währingerstrasse 42, A-1090 Wien, Austria.
authors: Atta U
authors: AU
authors: Khan
authors: G
authors: G
authors: Rogl
authors: M
authors: M
authors: Kriegisch
authors: H
authors: H
authors: Michor
authors: H
authors: H
authors: Müller
authors: E
authors: E
authors: Bauer
authors: A
authors: A
authors: Grytsiv
authors: G
authors: G
authors: Giester
authors: P
authors: P
authors: Rogl